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# tzdb data for North and Central America and environs
# This file is in the public domain, so clarified as of
# 2009-05-17 by Arthur David Olson.
# also includes Central America and the Caribbean
# This file is by no means authoritative; if you think you know better,
# go ahead and edit the file (and please send any changes to
# tz@iana.org for general use in the future). For more, please see
# the file CONTRIBUTING in the tz distribution.
# From Paul Eggert (1999-03-22):
# A reliable and entertaining source about time zones is
# Derek Howse, Greenwich time and longitude, Philip Wilson Publishers (1997).
###############################################################################
# United States
# From Paul Eggert (1999-03-31):
# Howse writes (pp 121-125) that time zones were invented by
# Professor Charles Ferdinand Dowd (1825-1904),
# Principal of Temple Grove Ladies' Seminary (Saratoga Springs, NY).
# His pamphlet "A System of National Time for Railroads" (1870)
# was the result of his proposals at the Convention of Railroad Trunk Lines
# in New York City (1869-10). His 1870 proposal was based on Washington, DC,
# but in 1872-05 he moved the proposed origin to Greenwich.
# From Paul Eggert (2018-03-20):
# Dowd's proposal left many details unresolved, such as where to draw
# lines between time zones. The key individual who made time zones
# work in the US was William Frederick Allen - railway engineer,
# managing editor of the Travelers' Guide, and secretary of the
# General Time Convention, a railway standardization group. Allen
# spent months in dialogs with scientific and railway leaders,
# developed a workable plan to institute time zones, and presented it
# to the General Time Convention on 1883-04-11, saying that his plan
# meant "local time would be practically abolished" - a plus for
# railway scheduling. By the next convention on 1883-10-11 nearly all
# railroads had agreed and it took effect on 1883-11-18. That Sunday
# was called the "day of two noons", as some locations observed noon
# twice. Allen witnessed the transition in New York City, writing:
#
# I heard the bells of St. Paul's strike on the old time. Four
# minutes later, obedient to the electrical signal from the Naval
# Observatory ... the time-ball made its rapid descent, the chimes
# of old Trinity rang twelve measured strokes, and local time was
# abandoned, probably forever.
#
# Most of the US soon followed suit. See:
# Bartky IR. The adoption of standard time. Technol Cult 1989 Jan;30(1):25-56.
# https://dx.doi.org/10.2307/3105430
# From Paul Eggert (2005-04-16):
# That 1883 transition occurred at 12:00 new time, not at 12:00 old time.
# See p 46 of David Prerau, Seize the daylight, Thunder's Mouth Press (2005).
# From Paul Eggert (2006-03-22):
# A good source for time zone historical data in the US is
# Thomas G. Shanks, The American Atlas (5th edition),
# San Diego: ACS Publications, Inc. (1991).
# Make sure you have the errata sheet; the book is somewhat useless without it.
# It is the source for most of the pre-1991 US entries below.
# From Paul Eggert (2001-03-06):
# Daylight Saving Time was first suggested as a joke by Benjamin Franklin
# in his whimsical essay "An Economical Project for Diminishing the Cost
# of Light" published in the Journal de Paris (1784-04-26).
# Not everyone is happy with the results:
#
# I don't really care how time is reckoned so long as there is some
# agreement about it, but I object to being told that I am saving
# daylight when my reason tells me that I am doing nothing of the kind.
# I even object to the implication that I am wasting something
# valuable if I stay in bed after the sun has risen. As an admirer
# of moonlight I resent the bossy insistence of those who want to
# reduce my time for enjoying it. At the back of the Daylight Saving
# scheme I detect the bony, blue-fingered hand of Puritanism, eager
# to push people into bed earlier, and get them up earlier, to make
# them healthy, wealthy and wise in spite of themselves.
#
# -- Robertson Davies, The diary of Samuel Marchbanks,
# Clarke, Irwin (1947), XIX, Sunday
#
# For more about the first ten years of DST in the United States, see
# Robert Garland, Ten years of daylight saving from the Pittsburgh standpoint
# (Carnegie Library of Pittsburgh, 1927).
# http://www.clpgh.org/exhibit/dst.html
#
# Shanks says that DST was called "War Time" in the US in 1918 and 1919.
# However, DST was imposed by the Standard Time Act of 1918, which
# was the first nationwide legal time standard, and apparently
# time was just called "Standard Time" or "Daylight Saving Time".
# From Arthur David Olson:
# US Daylight Saving Time ended on the last Sunday of *October* in 1974.
# See, for example, the front page of the Saturday, 1974-10-26
# and Sunday, 1974-10-27 editions of the Washington Post.
# From Arthur David Olson:
# Before the Uniform Time Act of 1966 took effect in 1967, observance of
# Daylight Saving Time in the US was by local option, except during wartime.
# From Arthur David Olson (2000-09-25):
# Last night I heard part of a rebroadcast of a 1945 Arch Oboler radio drama.
# In the introduction, Oboler spoke of "Eastern Peace Time."
# An AltaVista search turned up:
# https://web.archive.org/web/20000926032210/http://rowayton.org/rhs/hstaug45.html
# "When the time is announced over the radio now, it is 'Eastern Peace
# Time' instead of the old familiar 'Eastern War Time.' Peace is wonderful."
# (August 1945) by way of confirmation.
#
# From Paul Eggert (2017-09-23):
# This was the V-J Day issue of the Clamdigger, a Rowayton, CT newsletter.
# From Joseph Gallant citing
# George H. Douglas, _The Early Days of Radio Broadcasting_ (1987):
# At 7 P.M. (Eastern War Time) [on 1945-08-14], the networks were set
# to switch to London for Attlee's address, but the American people
# never got to hear his speech live. According to one press account,
# CBS' Bob Trout was first to announce the word of Japan's surrender,
# but a few seconds later, NBC, ABC and Mutual also flashed the word
# of surrender, all of whom interrupting the bells of Big Ben in
# London which were to precede Mr. Attlee's speech.
# From Paul Eggert (2003-02-09): It was Robert St John, not Bob Trout. From
# Myrna Oliver's obituary of St John on page B16 of today's Los Angeles Times:
#
# ... a war-weary U.S. clung to radios, awaiting word of Japan's surrender.
# Any announcement from Asia would reach St. John's New York newsroom on a
# wire service teletype machine, which had prescribed signals for major news.
# Associated Press, for example, would ring five bells before spewing out
# typed copy of an important story, and 10 bells for news "of transcendental
# importance."
#
# On Aug. 14, stalling while talking steadily into the NBC networks' open
# microphone, St. John heard five bells and waited only to hear a sixth bell,
# before announcing confidently: "Ladies and gentlemen, World War II is over.
# The Japanese have agreed to our surrender terms."
#
# He had scored a 20-second scoop on other broadcasters.
# From Arthur David Olson (2005-08-22):
# Paul has been careful to use the "US" rules only in those locations
# that are part of the United States; this reflects the real scope of
# U.S. government action. So even though the "US" rules have changed
# in the latest release, other countries won't be affected.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule US 1918 1919 - Mar lastSun 2:00 1:00 D
Rule US 1918 1919 - Oct lastSun 2:00 0 S
Rule US 1942 only - Feb 9 2:00 1:00 W # War
Rule US 1945 only - Aug 14 23:00u 1:00 P # Peace
Rule US 1945 only - Sep lastSun 2:00 0 S
Rule US 1967 2006 - Oct lastSun 2:00 0 S
Rule US 1967 1973 - Apr lastSun 2:00 1:00 D
Rule US 1974 only - Jan 6 2:00 1:00 D
Rule US 1975 only - Feb 23 2:00 1:00 D
Rule US 1976 1986 - Apr lastSun 2:00 1:00 D
Rule US 1987 2006 - Apr Sun>=1 2:00 1:00 D
Rule US 2007 max - Mar Sun>=8 2:00 1:00 D
Rule US 2007 max - Nov Sun>=1 2:00 0 S
# From Arthur David Olson, 2005-12-19
# We generate the files specified below to guard against old files with
# obsolete information being left in the time zone binary directory.
# We limit the list to names that have appeared in previous versions of
# this time zone package.
# We do these as separate Zones rather than as Links to avoid problems if
# a particular place changes whether it observes DST.
# We put these specifications here in the northamerica file both to
# increase the chances that they'll actually get compiled and to
# avoid the need to duplicate the US rules in another file.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone EST -5:00 - EST
Zone MST -7:00 - MST
Zone HST -10:00 - HST
Zone EST5EDT -5:00 US E%sT
Zone CST6CDT -6:00 US C%sT
Zone MST7MDT -7:00 US M%sT
Zone PST8PDT -8:00 US P%sT
# From U. S. Naval Observatory (1989-01-19):
# USA EASTERN 5 H BEHIND UTC NEW YORK, WASHINGTON
# USA EASTERN 4 H BEHIND UTC APR 3 - OCT 30
# USA CENTRAL 6 H BEHIND UTC CHICAGO, HOUSTON
# USA CENTRAL 5 H BEHIND UTC APR 3 - OCT 30
# USA MOUNTAIN 7 H BEHIND UTC DENVER
# USA MOUNTAIN 6 H BEHIND UTC APR 3 - OCT 30
# USA PACIFIC 8 H BEHIND UTC L.A., SAN FRANCISCO
# USA PACIFIC 7 H BEHIND UTC APR 3 - OCT 30
# USA ALASKA STD 9 H BEHIND UTC MOST OF ALASKA (AKST)
# USA ALASKA STD 8 H BEHIND UTC APR 3 - OCT 30 (AKDT)
# USA ALEUTIAN 10 H BEHIND UTC ISLANDS WEST OF 170W
# USA " 9 H BEHIND UTC APR 3 - OCT 30
# USA HAWAII 10 H BEHIND UTC
# USA BERING 11 H BEHIND UTC SAMOA, MIDWAY
# From Arthur David Olson (1989-01-21):
# The above dates are for 1988.
# Note the "AKST" and "AKDT" abbreviations, the claim that there's
# no DST in Samoa, and the claim that there is DST in Alaska and the
# Aleutians.
# From Arthur David Olson (1988-02-13):
# Legal standard time zone names, from United States Code (1982 Edition and
# Supplement III), Title 15, Chapter 6, Section 260 and forward. First, names
# up to 1967-04-01 (when most provisions of the Uniform Time Act of 1966
# took effect), as explained in sections 263 and 261:
# (none)
# United States standard eastern time
# United States standard mountain time
# United States standard central time
# United States standard Pacific time
# (none)
# United States standard Alaska time
# (none)
# Next, names from 1967-04-01 until 1983-11-30 (the date for
# public law 98-181):
# Atlantic standard time
# eastern standard time
# central standard time
# mountain standard time
# Pacific standard time
# Yukon standard time
# Alaska-Hawaii standard time
# Bering standard time
# And after 1983-11-30:
# Atlantic standard time
# eastern standard time
# central standard time
# mountain standard time
# Pacific standard time
# Alaska standard time
# Hawaii-Aleutian standard time
# Samoa standard time
# The law doesn't give abbreviations.
#
# From Paul Eggert (2016-12-19):
# Here are URLs for the 1918 and 1966 legislation:
# http://uscode.house.gov/statviewer.htm?volume=40&page=451
# http://uscode.house.gov/statviewer.htm?volume=80&page=108
# Although the 1918 names were officially "United States Standard
# Eastern Time" and similarly for "Central", "Mountain", "Pacific",
# and "Alaska", in practice "Standard" was placed just before "Time",
# as codified in 1966. In practice, Alaska time was abbreviated "AST"
# before 1968. Summarizing the 1967 name changes:
# 1918 names 1967 names
# -08 Standard Pacific Time (PST) Pacific standard time (PST)
# -09 (unofficial) Yukon (YST) Yukon standard time (YST)
# -10 Standard Alaska Time (AST) Alaska-Hawaii standard time (AHST)
# -11 (unofficial) Nome (NST) Bering standard time (BST)
#
# From Paul Eggert (2000-01-08), following a heads-up from Rives McDow:
# Public law 106-564 (2000-12-23) introduced ... "Chamorro Standard Time"
# for time in Guam and the Northern Marianas. See the file "australasia".
#
# From Paul Eggert (2015-04-17):
# HST and HDT are standardized abbreviations for Hawaii-Aleutian
# standard and daylight times. See section 9.47 (p 234) of the
# U.S. Government Printing Office Style Manual (2008)
# https://www.gpo.gov/fdsys/pkg/GPO-STYLEMANUAL-2008/pdf/GPO-STYLEMANUAL-2008.pdf
# From Arthur David Olson, 2005-08-09
# The following was signed into law on 2005-08-08.
#
# H.R. 6, Energy Policy Act of 2005, SEC. 110. DAYLIGHT SAVINGS.
# (a) Amendment.--Section 3(a) of the Uniform Time Act of 1966 (15
# U.S.C. 260a(a)) is amended--
# (1) by striking "first Sunday of April" and inserting "second
# Sunday of March"; and
# (2) by striking "last Sunday of October" and inserting "first
# Sunday of November'.
# (b) Effective Date.--Subsection (a) shall take effect 1 year after the
# date of enactment of this Act or March 1, 2007, whichever is later.
# (c) Report to Congress.--Not later than 9 months after the effective
# date stated in subsection (b), the Secretary shall report to Congress
# on the impact of this section on energy consumption in the United
# States.
# (d) Right to Revert.--Congress retains the right to revert the
# Daylight Saving Time back to the 2005 time schedules once the
# Department study is complete.
# US eastern time, represented by New York
# Connecticut, Delaware, District of Columbia, most of Florida,
# Georgia, southeast Indiana (Dearborn and Ohio counties), eastern Kentucky
# (except America/Kentucky/Louisville below), Maine, Maryland, Massachusetts,
# New Hampshire, New Jersey, New York, North Carolina, Ohio,
# Pennsylvania, Rhode Island, South Carolina, eastern Tennessee,
# Vermont, Virginia, West Virginia
# From Dave Cantor (2004-11-02):
# Early this summer I had the occasion to visit the Mount Washington
# Observatory weather station atop (of course!) Mount Washington [, NH]....
# One of the staff members said that the station was on Eastern Standard Time
# and didn't change their clocks for Daylight Saving ... so that their
# reports will always have times which are 5 hours behind UTC.
# From Paul Eggert (2005-08-26):
# According to today's Huntsville Times
# http://www.al.com/news/huntsvilletimes/index.ssf?/base/news/1125047783228320.xml&coll=1
# a few towns on Alabama's "eastern border with Georgia, such as Phenix City
# in Russell County, Lanett in Chambers County and some towns in Lee County,
# set their watches and clocks on Eastern time." It quotes H.H. "Bubba"
# Roberts, city administrator in Phenix City. as saying "We are in the Central
# time zone, but we do go by the Eastern time zone because so many people work
# in Columbus."
#
# From Paul Eggert (2017-02-22):
# Four cities are involved. The two not mentioned above are Smiths Station
# and Valley. Barbara Brooks, Valley's assistant treasurer, heard it started
# because West Point Pepperell textile mills were in Alabama while the
# corporate office was in Georgia, and residents voted to keep Eastern
# time even after the mills closed. See: Kazek K. Did you know which
# Alabama towns are in a different time zone? al.com 2017-02-06.
# http://www.al.com/living/index.ssf/2017/02/do_you_know_which_alabama_town.html
# From Paul Eggert (2014-09-06):
# Monthly Notices of the Royal Astronomical Society 44, 4 (1884-02-08), 208
# says that New York City Hall time was 3 minutes 58.4 seconds fast of
# Eastern time (i.e., -4:56:01.6) just before the 1883 switch. Round to the
# nearest second.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER
Rule NYC 1920 only - Mar lastSun 2:00 1:00 D
Rule NYC 1920 only - Oct lastSun 2:00 0 S
Rule NYC 1921 1966 - Apr lastSun 2:00 1:00 D
Rule NYC 1921 1954 - Sep lastSun 2:00 0 S
Rule NYC 1955 1966 - Oct lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/New_York -4:56:02 - LMT 1883 Nov 18 12:03:58
-5:00 US E%sT 1920
-5:00 NYC E%sT 1942
-5:00 US E%sT 1946
-5:00 NYC E%sT 1967
-5:00 US E%sT
# US central time, represented by Chicago
# Alabama, Arkansas, Florida panhandle (Bay, Calhoun, Escambia,
# Gulf, Holmes, Jackson, Okaloosa, Santa Rosa, Walton, and
# Washington counties), Illinois, western Indiana
# (Gibson, Jasper, Lake, LaPorte, Newton, Porter, Posey, Spencer,
# Vanderburgh, and Warrick counties), Iowa, most of Kansas, western
# Kentucky, Louisiana, Minnesota, Mississippi, Missouri, eastern
# Nebraska, eastern North Dakota, Oklahoma, eastern South Dakota,
# western Tennessee, most of Texas, Wisconsin
# From Paul Eggert (2018-01-07):
# In 1869 the Chicago Astronomical Society contracted with the city to keep
# time. Though delayed by the Great Fire, by 1880 a wire ran from the
# Dearborn Observatory (on the University of Chicago campus) to City Hall,
# which then sent signals to police and fire stations. However, railroads got
# their time signals from the Allegheny Observatory, the Madison Observatory,
# the Ann Arbor Observatory, etc., so their clocks did not agree with each
# other or with the city's official time. The confusion took some years to
# clear up. See:
# Moser M. How Chicago gave America its time zones. Chicago. 2018-01-04.
# http://www.chicagomag.com/city-life/January-2018/How-Chicago-Gave-America-Its-Time-Zones/
# From Larry M. Smith (2006-04-26) re Wisconsin:
# https://docs.legis.wisconsin.gov/statutes/statutes/175.pdf
# is currently enforced at the 01:00 time of change. Because the local
# "bar time" in the state corresponds to 02:00, a number of citations
# are issued for the "sale of class 'B' alcohol after prohibited
# hours" within the deviated hour of this change every year....
#
# From Douglas R. Bomberg (2007-03-12):
# Wisconsin has enacted (nearly eleventh-hour) legislation to get WI
# Statue 175 closer in synch with the US Congress' intent....
# https://docs.legis.wisconsin.gov/2007/related/acts/3
# From an email administrator of the City of Fort Pierre, SD (2015-12-21):
# Fort Pierre is technically located in the Mountain time zone as is
# the rest of Stanley County. Most of Stanley County and Fort Pierre
# uses the Central time zone due to doing most of their business in
# Pierre so it simplifies schedules. I have lived in Stanley County
# all my life and it has been that way since I can remember. (43 years!)
#
# From Paul Eggert (2015-12-25):
# Assume this practice predates 1970, so Fort Pierre can use America/Chicago.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER
Rule Chicago 1920 only - Jun 13 2:00 1:00 D
Rule Chicago 1920 1921 - Oct lastSun 2:00 0 S
Rule Chicago 1921 only - Mar lastSun 2:00 1:00 D
Rule Chicago 1922 1966 - Apr lastSun 2:00 1:00 D
Rule Chicago 1922 1954 - Sep lastSun 2:00 0 S
Rule Chicago 1955 1966 - Oct lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Chicago -5:50:36 - LMT 1883 Nov 18 12:09:24
-6:00 US C%sT 1920
-6:00 Chicago C%sT 1936 Mar 1 2:00
-5:00 - EST 1936 Nov 15 2:00
-6:00 Chicago C%sT 1942
-6:00 US C%sT 1946
-6:00 Chicago C%sT 1967
-6:00 US C%sT
# Oliver County, ND switched from mountain to central time on 1992-10-25.
Zone America/North_Dakota/Center -6:45:12 - LMT 1883 Nov 18 12:14:48
-7:00 US M%sT 1992 Oct 25 2:00
-6:00 US C%sT
# Morton County, ND, switched from mountain to central time on
# 2003-10-26, except for the area around Mandan which was already central time.
# See <http://dmses.dot.gov/docimages/p63/135818.pdf>.
# Officially this switch also included part of Sioux County, and
# Jones, Mellette, and Todd Counties in South Dakota;
# but in practice these other counties were already observing central time.
# See <http://www.epa.gov/fedrgstr/EPA-IMPACT/2003/October/Day-28/i27056.htm>.
Zone America/North_Dakota/New_Salem -6:45:39 - LMT 1883 Nov 18 12:14:21
-7:00 US M%sT 2003 Oct 26 2:00
-6:00 US C%sT
# From Josh Findley (2011-01-21):
# ...it appears that Mercer County, North Dakota, changed from the
# mountain time zone to the central time zone at the last transition from
# daylight-saving to standard time (on Nov. 7, 2010):
# https://www.gpo.gov/fdsys/pkg/FR-2010-09-29/html/2010-24376.htm
# http://www.bismarcktribune.com/news/local/article_1eb1b588-c758-11df-b472-001cc4c03286.html
# From Andy Lipscomb (2011-01-24):
# ...according to the Census Bureau, the largest city is Beulah (although
# it's commonly referred to as Beulah-Hazen, with Hazen being the next
# largest city in Mercer County). Google Maps places Beulah's city hall
# at 47° 15' 51" N, 101° 46' 40" W, which yields an offset of 6h47'07".
Zone America/North_Dakota/Beulah -6:47:07 - LMT 1883 Nov 18 12:12:53
-7:00 US M%sT 2010 Nov 7 2:00
-6:00 US C%sT
# US mountain time, represented by Denver
#
# Colorado, far western Kansas, Montana, western
# Nebraska, Nevada border (Jackpot, Owyhee, and Mountain City),
# New Mexico, southwestern North Dakota,
# western South Dakota, far western Texas (El Paso County, Hudspeth County,
# and Pine Springs and Nickel Creek in Culberson County), Utah, Wyoming
#
# From Paul Eggert (2018-10-25):
# On 1921-03-04 federal law placed all of Texas into the central time zone.
# However, El Paso ignored the law for decades and continued to observe
# mountain time, on the grounds that that's what they had always done
# and they weren't about to let the federal government tell them what to do.
# Eventually the federal government gave in and changed the law on
# 1970-04-10 to match what El Paso was actually doing. Although
# that's slightly after our 1970 cutoff, there is no need to create a
# separate zone for El Paso since they were ignoring the law anyway. See:
# Long T. El Pasoans were time rebels, fought to stay in Mountain zone.
# El Paso Times. 2018-10-24 06:40 -06.
# https://www.elpasotimes.com/story/news/local/el-paso/2018/10/24/el-pasoans-were-time-rebels-fought-stay-mountain-zone/1744509002/
#
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER
Rule Denver 1920 1921 - Mar lastSun 2:00 1:00 D
Rule Denver 1920 only - Oct lastSun 2:00 0 S
Rule Denver 1921 only - May 22 2:00 0 S
Rule Denver 1965 1966 - Apr lastSun 2:00 1:00 D
Rule Denver 1965 1966 - Oct lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Denver -6:59:56 - LMT 1883 Nov 18 12:00:04
-7:00 US M%sT 1920
-7:00 Denver M%sT 1942
-7:00 US M%sT 1946
-7:00 Denver M%sT 1967
-7:00 US M%sT
# US Pacific time, represented by Los Angeles
#
# California, northern Idaho (Benewah, Bonner, Boundary, Clearwater,
# Kootenai, Latah, Lewis, Nez Perce, and Shoshone counties, Idaho county
# north of the Salmon River, and the towns of Burgdorf and Warren),
# Nevada (except West Wendover), Oregon (except the northern ¾ of
# Malheur county), and Washington
# From Paul Eggert (2016-08-20):
# In early February 1948, in response to California's electricity shortage,
# PG&E changed power frequency from 60 to 59.5 Hz during daylight hours,
# causing electric clocks to lose six minutes per day. (This did not change
# legal time, and is not part of the data here.) See:
# Ross SA. An energy crisis from the past: Northern California in 1948.
# Working Paper No. 8, Institute of Governmental Studies, UC Berkeley,
# 1973-11. https://escholarship.org/uc/item/8x22k30c
#
# In another measure to save electricity, DST was instituted from 1948-03-14
# at 02:01 to 1949-01-16 at 02:00, with the governor having the option to move
# the fallback transition earlier. See pages 3-4 of:
# http://clerk.assembly.ca.gov/sites/clerk.assembly.ca.gov/files/archive/Statutes/1948/48Vol1_Chapters.pdf
#
# In response:
#
# Governor Warren received a torrent of objecting mail, and it is not too much
# to speculate that the objections to Daylight Saving Time were one important
# factor in the defeat of the Dewey-Warren Presidential ticket in California.
# -- Ross, p 25
#
# On December 8 the governor exercised the option, setting the date to January 1
# (LA Times 1948-12-09). The transition time was 02:00 (LA Times 1949-01-01).
#
# Despite the controversy, in 1949 California voters approved Proposition 12,
# which established DST from April's last Sunday at 01:00 until September's
# last Sunday at 02:00. This was amended by 1962's Proposition 6, which changed
# the fall-back date to October's last Sunday. See:
# https://repository.uchastings.edu/cgi/viewcontent.cgi?article=1501&context=ca_ballot_props
# https://repository.uchastings.edu/cgi/viewcontent.cgi?article=1636&context=ca_ballot_props
#
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER
Rule CA 1948 only - Mar 14 2:01 1:00 D
Rule CA 1949 only - Jan 1 2:00 0 S
Rule CA 1950 1966 - Apr lastSun 1:00 1:00 D
Rule CA 1950 1961 - Sep lastSun 2:00 0 S
Rule CA 1962 1966 - Oct lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Los_Angeles -7:52:58 - LMT 1883 Nov 18 12:07:02
-8:00 US P%sT 1946
-8:00 CA P%sT 1967
-8:00 US P%sT
# Alaska
# AK%sT is the modern abbreviation for -09 per USNO.
#
# From Paul Eggert (2017-06-15):
# Howse writes that Alaska switched from the Julian to the Gregorian calendar,
# and from east-of-GMT to west-of-GMT days, when the US bought it from Russia.
# On Friday, 1867-10-18 (Gregorian), at precisely 15:30 local time, the
# Russian forts and fleet at Sitka fired salutes to mark the ceremony of
# formal transfer. See the Sacramento Daily Union (1867-11-14), p 3, col 2.
# https://cdnc.ucr.edu/cgi-bin/cdnc?a=d&d=SDU18671114.2.12.1
# Sitka workers did not change their calendars until Sunday, 1867-10-20,
# and so celebrated two Sundays that week. See: Ahllund T (tr Hallamaa P).
# From the memoirs of a Finnish workman. Alaska History. 2006 Fall;21(2):1-25.
# http://alaskahistoricalsociety.org/wp-content/uploads/2016/12/Ahllund-2006-Memoirs-of-a-Finnish-Workman.pdf
# Include only the time zone part of this transition, ignoring the switch
# from Julian to Gregorian, since we can't represent the Julian calendar.
#
# As far as we know, of the locations mentioned below only Sitka was
# permanently inhabited in 1867 by anyone using either calendar.
# (Yakutat was colonized by the Russians in 1799, but the settlement was
# destroyed in 1805 by a Yakutat-kon war party.) Many of Alaska's inhabitants
# were unaware of the US acquisition of Alaska, much less of any calendar or
# time change. However, the Russian-influenced part of Alaska did observe
# Russian time, and it is more accurate to model this than to ignore it.
# The database format requires an exact transition time; use the Russian
# salute as a somewhat-arbitrary time for the formal transfer of control for
# all of Alaska. Sitka's UTC offset is -9:01:13; adjust its 15:30 to the
# local times of other Alaskan locations so that they change simultaneously.
# From Paul Eggert (2014-07-18):
# One opinion of the early-1980s turmoil in Alaska over time zones and
# daylight saving time appeared as graffiti on a Juneau airport wall:
# "Welcome to Juneau. Please turn your watch back to the 19th century."
# See: Turner W. Alaska's four time zones now two. NY Times 1983-11-01.
# http://www.nytimes.com/1983/11/01/us/alaska-s-four-time-zones-now-two.html
#
# Steve Ferguson (2011-01-31) referred to the following source:
# Norris F. Keeping time in Alaska: national directives, local response.
# Alaska History 2001;16(1-2).
# http://alaskahistoricalsociety.org/discover-alaska/glimpses-of-the-past/keeping-time-in-alaska/
# From Arthur David Olson (2011-02-01):
# Here's database-relevant material from the 2001 "Alaska History" article:
#
# On September 20 [1979]...DOT...officials decreed that on April 27,
# 1980, Juneau and other nearby communities would move to Yukon Time.
# Sitka, Petersburg, Wrangell, and Ketchikan, however, would remain on
# Pacific Time.
#
# ...on September 22, 1980, DOT Secretary Neil E. Goldschmidt rescinded the
# Department's September 1979 decision. Juneau and other communities in
# northern Southeast reverted to Pacific Time on October 26.
#
# On October 28 [1983]...the Metlakatla Indian Community Council voted
# unanimously to keep the reservation on Pacific Time.
#
# According to DOT official Joanne Petrie, Indian reservations are not
# bound to follow time zones imposed by neighboring jurisdictions.
#
# (The last is consistent with how the database now handles the Navajo
# Nation.)
# From Arthur David Olson (2011-02-09):
# I just spoke by phone with a staff member at the Metlakatla Indian
# Community office (using contact information available at
# http://www.commerce.state.ak.us/dca/commdb/CIS.cfm?Comm_Boro_name=Metlakatla
# It's shortly after 1:00 here on the east coast of the United States;
# the staffer said it was shortly after 10:00 there. When I asked whether
# that meant they were on Pacific time, they said no - they were on their
# own time. I asked about daylight saving; they said it wasn't used. I
# did not inquire about practices in the past.
# From Arthur David Olson (2011-08-17):
# For lack of better information, assume that Metlakatla's
# abandonment of use of daylight saving resulted from the 1983 vote.
# From Steffen Thorsen (2015-11-09):
# It seems Metlakatla did go off PST on Sunday, November 1, changing
# their time to AKST and are going to follow Alaska's DST, switching
# between AKST and AKDT from now on....
# https://www.krbd.org/2015/10/30/annette-island-times-they-are-a-changing/
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Juneau 15:02:19 - LMT 1867 Oct 19 15:33:32
-8:57:41 - LMT 1900 Aug 20 12:00
-8:00 - PST 1942
-8:00 US P%sT 1946
-8:00 - PST 1969
-8:00 US P%sT 1980 Apr 27 2:00
-9:00 US Y%sT 1980 Oct 26 2:00
-8:00 US P%sT 1983 Oct 30 2:00
-9:00 US Y%sT 1983 Nov 30
-9:00 US AK%sT
Zone America/Sitka 14:58:47 - LMT 1867 Oct 19 15:30
-9:01:13 - LMT 1900 Aug 20 12:00
-8:00 - PST 1942
-8:00 US P%sT 1946
-8:00 - PST 1969
-8:00 US P%sT 1983 Oct 30 2:00
-9:00 US Y%sT 1983 Nov 30
-9:00 US AK%sT
Zone America/Metlakatla 15:13:42 - LMT 1867 Oct 19 15:44:55
-8:46:18 - LMT 1900 Aug 20 12:00
-8:00 - PST 1942
-8:00 US P%sT 1946
-8:00 - PST 1969
-8:00 US P%sT 1983 Oct 30 2:00
-8:00 - PST 2015 Nov 1 2:00
-9:00 US AK%sT
Zone America/Yakutat 14:41:05 - LMT 1867 Oct 19 15:12:18
-9:18:55 - LMT 1900 Aug 20 12:00
-9:00 - YST 1942
-9:00 US Y%sT 1946
-9:00 - YST 1969
-9:00 US Y%sT 1983 Nov 30
-9:00 US AK%sT
Zone America/Anchorage 14:00:24 - LMT 1867 Oct 19 14:31:37
-9:59:36 - LMT 1900 Aug 20 12:00
-10:00 - AST 1942
-10:00 US A%sT 1967 Apr
-10:00 - AHST 1969
-10:00 US AH%sT 1983 Oct 30 2:00
-9:00 US Y%sT 1983 Nov 30
-9:00 US AK%sT
Zone America/Nome 12:58:22 - LMT 1867 Oct 19 13:29:35
-11:01:38 - LMT 1900 Aug 20 12:00
-11:00 - NST 1942
-11:00 US N%sT 1946
-11:00 - NST 1967 Apr
-11:00 - BST 1969
-11:00 US B%sT 1983 Oct 30 2:00
-9:00 US Y%sT 1983 Nov 30
-9:00 US AK%sT
Zone America/Adak 12:13:22 - LMT 1867 Oct 19 12:44:35
-11:46:38 - LMT 1900 Aug 20 12:00
-11:00 - NST 1942
-11:00 US N%sT 1946
-11:00 - NST 1967 Apr
-11:00 - BST 1969
-11:00 US B%sT 1983 Oct 30 2:00
-10:00 US AH%sT 1983 Nov 30
-10:00 US H%sT
# The following switches don't quite make our 1970 cutoff.
#
# Shanks writes that part of southwest Alaska (e.g. Aniak)
# switched from -11:00 to -10:00 on 1968-09-22 at 02:00,
# and another part (e.g. Akiak) made the same switch five weeks later.
#
# From David Flater (2004-11-09):
# In e-mail, 2004-11-02, Ray Hudson, historian/liaison to the Unalaska
# Historic Preservation Commission, provided this information, which
# suggests that Unalaska deviated from statutory time from early 1967
# possibly until 1983:
#
# Minutes of the Unalaska City Council Meeting, January 10, 1967:
# "Except for St. Paul and Akutan, Unalaska is the only important
# location not on Alaska Standard Time. The following resolution was
# made by William Robinson and seconded by Henry Swanson: Be it
# resolved that the City of Unalaska hereby goes to Alaska Standard
# Time as of midnight Friday, January 13, 1967 (1 A.M. Saturday,
# January 14, Alaska Standard Time.) This resolution was passed with
# three votes for and one against."
# Hawaii
# From Arthur David Olson (2010-12-09):
# "Hawaiian Time" by Robert C. Schmitt and Doak C. Cox appears on pages 207-225
# of volume 26 of The Hawaiian Journal of History (1992). As of 2010-12-09,
# the article is available at
# https://evols.library.manoa.hawaii.edu/bitstream/10524/239/2/JL26215.pdf
# and indicates that standard time was adopted effective noon, January
# 13, 1896 (page 218), that in "1933, the Legislature decreed daylight
# saving for the period between the last Sunday of each April and the
# last Sunday of each September, but less than a month later repealed the
# act," (page 220), that year-round daylight saving time was in effect
# from 1942-02-09 to 1945-09-30 (page 221, with no time of day given for
# when clocks changed) and that clocks were changed by 30 minutes
# effective the second Sunday of June, 1947 (page 219, with no time of
# day given for when clocks changed). A footnote for the 1933 changes
# cites Session Laws of Hawaii 1933, "Act. 90 (approved 26 Apr. 1933)
# and Act 163 (approved 21 May 1933)."
# From Arthur David Olson (2011-01-19):
# The following is from "Laws of the Territory of Hawaii Passed by the
# Seventeenth Legislature: Regular Session 1933," available (as of
# 2011-01-19) at American University's Pence Law Library. Page 85: "Act
# 90...At 2 o'clock ante meridian of the last Sunday in April of each
# year, the standard time of this Territory shall be advanced one
# hour...This Act shall take effect upon its approval. Approved this 26th
# day of April, A. D. 1933. LAWRENCE M JUDD, Governor of the Territory of
# Hawaii." Page 172: "Act 163...Act 90 of the Session Laws of 1933 is
# hereby repealed...This Act shall take effect upon its approval, upon
# which date the standard time of this Territory shall be restored to
# that existing immediately prior to the taking effect of said Act 90.
# Approved this 21st day of May, A. D. 1933. LAWRENCE M. JUDD, Governor
# of the Territory of Hawaii."
#
# Note that 1933-05-21 was a Sunday.
# We're left to guess the time of day when Act 163 was approved; guess noon.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone Pacific/Honolulu -10:31:26 - LMT 1896 Jan 13 12:00
-10:30 - HST 1933 Apr 30 2:00
-10:30 1:00 HDT 1933 May 21 12:00
-10:30 US H%sT 1947 Jun 8 2:00
-10:00 - HST
# Now we turn to US areas that have diverged from the consensus since 1970.
# Arizona mostly uses MST.
# From Paul Eggert (2002-10-20):
#
# The information in the rest of this paragraph is derived from the
# Daylight Saving Time web page
# <http://www.dlapr.lib.az.us/links/daylight.htm> (2002-01-23)
# maintained by the Arizona State Library, Archives and Public Records.
# Between 1944-01-01 and 1944-04-01 the State of Arizona used standard
# time, but by federal law railroads, airlines, bus lines, military
# personnel, and some engaged in interstate commerce continued to
# observe war (i.e., daylight saving) time. The 1944-03-17 Phoenix
# Gazette says that was the date the law changed, and that 04-01 was
# the date the state's clocks would change. In 1945 the State of
# Arizona used standard time all year, again with exceptions only as
# mandated by federal law. Arizona observed DST in 1967, but Arizona
# Laws 1968, ch. 183 (effective 1968-03-21) repealed DST.
#
# Shanks says the 1944 experiment came to an end on 1944-03-17.
# Go with the Arizona State Library instead.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Phoenix -7:28:18 - LMT 1883 Nov 18 11:31:42
-7:00 US M%sT 1944 Jan 1 0:01
-7:00 - MST 1944 Apr 1 0:01
-7:00 US M%sT 1944 Oct 1 0:01
-7:00 - MST 1967
-7:00 US M%sT 1968 Mar 21
-7:00 - MST
# From Arthur David Olson (1988-02-13):
# A writer from the Inter Tribal Council of Arizona, Inc.,
# notes in private correspondence dated 1987-12-28 that "Presently, only the
# Navajo Nation participates in the Daylight Saving Time policy, due to its
# large size and location in three states." (The "only" means that other
# tribal nations don't use DST.)
#
# From Paul Eggert (2013-08-26):
# See America/Denver for a zone appropriate for the Navajo Nation.
# Southern Idaho (Ada, Adams, Bannock, Bear Lake, Bingham, Blaine,
# Boise, Bonneville, Butte, Camas, Canyon, Caribou, Cassia, Clark,
# Custer, Elmore, Franklin, Fremont, Gem, Gooding, Jefferson, Jerome,
# Lemhi, Lincoln, Madison, Minidoka, Oneida, Owyhee, Payette, Power,
# Teton, Twin Falls, Valley, Washington counties, and the southern
# quarter of Idaho county) and eastern Oregon (most of Malheur County)
# switched four weeks late in 1974.
#
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Boise -7:44:49 - LMT 1883 Nov 18 12:15:11
-8:00 US P%sT 1923 May 13 2:00
-7:00 US M%sT 1974
-7:00 - MST 1974 Feb 3 2:00
-7:00 US M%sT
# Indiana
#
# For a map of Indiana's time zone regions, see:
# https://en.wikipedia.org/wiki/Time_in_Indiana
#
# From Paul Eggert (2007-08-17):
# Since 1970, most of Indiana has been like America/Indiana/Indianapolis,
# with the following exceptions:
#
# - Gibson, Jasper, Lake, LaPorte, Newton, Porter, Posey, Spencer,
# Vanderburgh, and Warrick counties have been like America/Chicago.
#
# - Dearborn and Ohio counties have been like America/New_York.
#
# - Clark, Floyd, and Harrison counties have been like
# America/Kentucky/Louisville.
#
# - Crawford, Daviess, Dubois, Knox, Martin, Perry, Pike, Pulaski, Starke,
# and Switzerland counties have their own time zone histories as noted below.
#
# Shanks partitioned Indiana into 345 regions, each with its own time history,
# and wrote "Even newspaper reports present contradictory information."
# Those Hoosiers! Such a flighty and changeable people!
# Fortunately, most of the complexity occurred before our cutoff date of 1970.
#
# Other than Indianapolis, the Indiana place names are so nondescript
# that they would be ambiguous if we left them at the 'America' level.
# So we reluctantly put them all in a subdirectory 'America/Indiana'.
# From Paul Eggert (2014-06-26):
# https://www.federalregister.gov/articles/2006/01/20/06-563/standard-time-zone-boundary-in-the-state-of-indiana
# says "DOT is relocating the time zone boundary in Indiana to move Starke,
# Pulaski, Knox, Daviess, Martin, Pike, Dubois, and Perry Counties from the
# Eastern Time Zone to the Central Time Zone.... The effective date of
# this rule is 2 a.m. EST Sunday, April 2, 2006, which is the
# changeover date from standard time to Daylight Saving Time."
# Strictly speaking, this meant the affected counties changed their
# clocks twice that night, but this obviously was in error. The intent
# was that 01:59:59 EST be followed by 02:00:00 CDT.
# From Gwillim Law (2007-02-10):
# The Associated Press has been reporting that Pulaski County, Indiana is
# going to switch from Central to Eastern Time on March 11, 2007....
# http://www.indystar.com/apps/pbcs.dll/article?AID=/20070207/LOCAL190108/702070524/0/LOCAL
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER
Rule Indianapolis 1941 only - Jun 22 2:00 1:00 D
Rule Indianapolis 1941 1954 - Sep lastSun 2:00 0 S
Rule Indianapolis 1946 1954 - Apr lastSun 2:00 1:00 D
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Indiana/Indianapolis -5:44:38 - LMT 1883 Nov 18 12:15:22
-6:00 US C%sT 1920
-6:00 Indianapolis C%sT 1942
-6:00 US C%sT 1946
-6:00 Indianapolis C%sT 1955 Apr 24 2:00
-5:00 - EST 1957 Sep 29 2:00
-6:00 - CST 1958 Apr 27 2:00
-5:00 - EST 1969
-5:00 US E%sT 1971
-5:00 - EST 2006
-5:00 US E%sT
#
# Eastern Crawford County, Indiana, left its clocks alone in 1974,
# as well as from 1976 through 2005.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER
Rule Marengo 1951 only - Apr lastSun 2:00 1:00 D
Rule Marengo 1951 only - Sep lastSun 2:00 0 S
Rule Marengo 1954 1960 - Apr lastSun 2:00 1:00 D
Rule Marengo 1954 1960 - Sep lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Indiana/Marengo -5:45:23 - LMT 1883 Nov 18 12:14:37
-6:00 US C%sT 1951
-6:00 Marengo C%sT 1961 Apr 30 2:00
-5:00 - EST 1969
-5:00 US E%sT 1974 Jan 6 2:00
-6:00 1:00 CDT 1974 Oct 27 2:00
-5:00 US E%sT 1976
-5:00 - EST 2006
-5:00 US E%sT
#
# Daviess, Dubois, Knox, and Martin Counties, Indiana,
# switched from eastern to central time in April 2006, then switched back
# in November 2007.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER
Rule Vincennes 1946 only - Apr lastSun 2:00 1:00 D
Rule Vincennes 1946 only - Sep lastSun 2:00 0 S
Rule Vincennes 1953 1954 - Apr lastSun 2:00 1:00 D
Rule Vincennes 1953 1959 - Sep lastSun 2:00 0 S
Rule Vincennes 1955 only - May 1 0:00 1:00 D
Rule Vincennes 1956 1963 - Apr lastSun 2:00 1:00 D
Rule Vincennes 1960 only - Oct lastSun 2:00 0 S
Rule Vincennes 1961 only - Sep lastSun 2:00 0 S
Rule Vincennes 1962 1963 - Oct lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Indiana/Vincennes -5:50:07 - LMT 1883 Nov 18 12:09:53
-6:00 US C%sT 1946
-6:00 Vincennes C%sT 1964 Apr 26 2:00
-5:00 - EST 1969
-5:00 US E%sT 1971
-5:00 - EST 2006 Apr 2 2:00
-6:00 US C%sT 2007 Nov 4 2:00
-5:00 US E%sT
#
# Perry County, Indiana, switched from eastern to central time in April 2006.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER
Rule Perry 1946 only - Apr lastSun 2:00 1:00 D
Rule Perry 1946 only - Sep lastSun 2:00 0 S
Rule Perry 1953 1954 - Apr lastSun 2:00 1:00 D
Rule Perry 1953 1959 - Sep lastSun 2:00 0 S
Rule Perry 1955 only - May 1 0:00 1:00 D
Rule Perry 1956 1963 - Apr lastSun 2:00 1:00 D
Rule Perry 1960 only - Oct lastSun 2:00 0 S
Rule Perry 1961 only - Sep lastSun 2:00 0 S
Rule Perry 1962 1963 - Oct lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Indiana/Tell_City -5:47:03 - LMT 1883 Nov 18 12:12:57
-6:00 US C%sT 1946
-6:00 Perry C%sT 1964 Apr 26 2:00
-5:00 - EST 1969
-5:00 US E%sT 1971
-5:00 - EST 2006 Apr 2 2:00
-6:00 US C%sT
#
# Pike County, Indiana moved from central to eastern time in 1977,
# then switched back in 2006, then switched back again in 2007.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER
Rule Pike 1955 only - May 1 0:00 1:00 D
Rule Pike 1955 1960 - Sep lastSun 2:00 0 S
Rule Pike 1956 1964 - Apr lastSun 2:00 1:00 D
Rule Pike 1961 1964 - Oct lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Indiana/Petersburg -5:49:07 - LMT 1883 Nov 18 12:10:53
-6:00 US C%sT 1955
-6:00 Pike C%sT 1965 Apr 25 2:00
-5:00 - EST 1966 Oct 30 2:00
-6:00 US C%sT 1977 Oct 30 2:00
-5:00 - EST 2006 Apr 2 2:00
-6:00 US C%sT 2007 Nov 4 2:00
-5:00 US E%sT
#
# Starke County, Indiana moved from central to eastern time in 1991,
# then switched back in 2006.
# From Arthur David Olson (1991-10-28):
# An article on page A3 of the Sunday, 1991-10-27 Washington Post
# notes that Starke County switched from Central time to Eastern time as of
# 1991-10-27.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER
Rule Starke 1947 1961 - Apr lastSun 2:00 1:00 D
Rule Starke 1947 1954 - Sep lastSun 2:00 0 S
Rule Starke 1955 1956 - Oct lastSun 2:00 0 S
Rule Starke 1957 1958 - Sep lastSun 2:00 0 S
Rule Starke 1959 1961 - Oct lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Indiana/Knox -5:46:30 - LMT 1883 Nov 18 12:13:30
-6:00 US C%sT 1947
-6:00 Starke C%sT 1962 Apr 29 2:00
-5:00 - EST 1963 Oct 27 2:00
-6:00 US C%sT 1991 Oct 27 2:00
-5:00 - EST 2006 Apr 2 2:00
-6:00 US C%sT
#
# Pulaski County, Indiana, switched from eastern to central time in
# April 2006 and then switched back in March 2007.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER
Rule Pulaski 1946 1960 - Apr lastSun 2:00 1:00 D
Rule Pulaski 1946 1954 - Sep lastSun 2:00 0 S
Rule Pulaski 1955 1956 - Oct lastSun 2:00 0 S
Rule Pulaski 1957 1960 - Sep lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Indiana/Winamac -5:46:25 - LMT 1883 Nov 18 12:13:35
-6:00 US C%sT 1946
-6:00 Pulaski C%sT 1961 Apr 30 2:00
-5:00 - EST 1969
-5:00 US E%sT 1971
-5:00 - EST 2006 Apr 2 2:00
-6:00 US C%sT 2007 Mar 11 2:00
-5:00 US E%sT
#
# Switzerland County, Indiana, did not observe DST from 1973 through 2005.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Indiana/Vevay -5:40:16 - LMT 1883 Nov 18 12:19:44
-6:00 US C%sT 1954 Apr 25 2:00
-5:00 - EST 1969
-5:00 US E%sT 1973
-5:00 - EST 2006
-5:00 US E%sT
# From Paul Eggert (2018-03-20):
# The Louisville & Nashville Railroad's 1883-11-18 change occurred at
# 10:00 old local time; train were supposed to come to a standstill
# for precisely 18 minutes. See Bartky Fig. 1 (page 50). It is not
# clear how this matched civil time in Louisville, so for now continue
# to assume Louisville switched at noon new local time, like New York.
#
# Part of Kentucky left its clocks alone in 1974.
# This also includes Clark, Floyd, and Harrison counties in Indiana.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER
Rule Louisville 1921 only - May 1 2:00 1:00 D
Rule Louisville 1921 only - Sep 1 2:00 0 S
Rule Louisville 1941 1961 - Apr lastSun 2:00 1:00 D
Rule Louisville 1941 only - Sep lastSun 2:00 0 S
Rule Louisville 1946 only - Jun 2 2:00 0 S
Rule Louisville 1950 1955 - Sep lastSun 2:00 0 S
Rule Louisville 1956 1960 - Oct lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Kentucky/Louisville -5:43:02 - LMT 1883 Nov 18 12:16:58
-6:00 US C%sT 1921
-6:00 Louisville C%sT 1942
-6:00 US C%sT 1946
-6:00 Louisville C%sT 1961 Jul 23 2:00
-5:00 - EST 1968
-5:00 US E%sT 1974 Jan 6 2:00
-6:00 1:00 CDT 1974 Oct 27 2:00
-5:00 US E%sT
#
# Wayne County, Kentucky
#
# From Lake Cumberland LIFE
# http://www.lake-cumberland.com/life/archive/news990129time.shtml
# (1999-01-29) via WKYM-101.7:
# Clinton County has joined Wayne County in asking the DoT to change from
# the Central to the Eastern time zone.... The Wayne County government made
# the same request in December. And while Russell County officials have not
# taken action, the majority of respondents to a poll conducted there in
# August indicated they would like to change to "fast time" also.
# The three Lake Cumberland counties are the farthest east of any U.S.
# location in the Central time zone.
#
# From Rich Wales (2000-08-29):
# After prolonged debate, and despite continuing deep differences of opinion,
# Wayne County (central Kentucky) is switching from Central (-0600) to Eastern
# (-0500) time. They won't "fall back" this year. See Sara Shipley,
# The difference an hour makes, Nando Times (2000-08-29 15:33 -0400).
#
# From Paul Eggert (2001-07-16):
# The final rule was published in the
# Federal Register 65, 160 (2000-08-17), pp 50154-50158.
# https://www.gpo.gov/fdsys/pkg/FR-2000-08-17/html/00-20854.htm
#
Zone America/Kentucky/Monticello -5:39:24 - LMT 1883 Nov 18 12:20:36
-6:00 US C%sT 1946
-6:00 - CST 1968
-6:00 US C%sT 2000 Oct 29 2:00
-5:00 US E%sT
# From Rives McDow (2000-08-30):
# Here ... are all the changes in the US since 1985.
# Kearny County, KS (put all of county on central;
# previously split between MST and CST) ... 1990-10
# Starke County, IN (from CST to EST) ... 1991-10
# Oliver County, ND (from MST to CST) ... 1992-10
# West Wendover, NV (from PST TO MST) ... 1999-10
# Wayne County, KY (from CST to EST) ... 2000-10
#
# From Paul Eggert (2001-07-17):
# We don't know where the line used to be within Kearny County, KS,
# so omit that change for now.
# See America/Indiana/Knox for the Starke County, IN change.
# See America/North_Dakota/Center for the Oliver County, ND change.
# West Wendover, NV officially switched from Pacific to mountain time on
# 1999-10-31. See the
# Federal Register 64, 203 (1999-10-21), pp 56705-56707.
# https://www.gpo.gov/fdsys/pkg/FR-1999-10-21/html/99-27240.htm
# However, the Federal Register says that West Wendover already operated
# on mountain time, and the rule merely made this official;
# hence a separate tz entry is not needed.
# Michigan
#
# From Bob Devine (1988-01-28):
# Michigan didn't observe DST from 1968 to 1973.
#
# From Paul Eggert (1999-03-31):
# Shanks writes that Michigan started using standard time on 1885-09-18,
# but Howse writes (pp 124-125, referring to Popular Astronomy, 1901-01)
# that Detroit kept
#
# local time until 1900 when the City Council decreed that clocks should
# be put back twenty-eight minutes to Central Standard Time. Half the
# city obeyed, half refused. After considerable debate, the decision
# was rescinded and the city reverted to Sun time. A derisive offer to
# erect a sundial in front of the city hall was referred to the
# Committee on Sewers. Then, in 1905, Central time was adopted
# by city vote.
#
# This story is too entertaining to be false, so go with Howse over Shanks.
#
# From Paul Eggert (2001-03-06):
# Garland (1927) writes "Cleveland and Detroit advanced their clocks
# one hour in 1914." This change is not in Shanks. We have no more
# info, so omit this for now.
#
# From Paul Eggert (2017-07-26):
# Although Shanks says Detroit observed DST in 1967 from 06-14 00:01
# until 10-29 00:01, I now see multiple reports that this is incorrect.
# For example, according to a 50-year anniversary report about the 1967
# Detroit riots and a major-league doubleheader on 1967-07-23, "By the time
# the last fly ball of the doubleheader settled into the glove of leftfielder
# Lenny Green, it was after 7 p.m. Detroit did not observe daylight saving
# time, so light was already starting to fail. Twilight was made even deeper
# by billowing columns of smoke that ascended in an unbroken wall north of the
# ballpark." See: Dow B. Detroit '67: As violence unfolded, Tigers played two
# at home vs. Yankees. Detroit Free Press 2017-07-23.
# https://www.freep.com/story/sports/mlb/tigers/2017/07/23/detroit-tigers-1967-riot-new-york-yankees/499951001/
#
# Most of Michigan observed DST from 1973 on, but was a bit late in 1975.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER
Rule Detroit 1948 only - Apr lastSun 2:00 1:00 D
Rule Detroit 1948 only - Sep lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Detroit -5:32:11 - LMT 1905
-6:00 - CST 1915 May 15 2:00
-5:00 - EST 1942
-5:00 US E%sT 1946
-5:00 Detroit E%sT 1973
-5:00 US E%sT 1975
-5:00 - EST 1975 Apr 27 2:00
-5:00 US E%sT
#
# Dickinson, Gogebic, Iron, and Menominee Counties, Michigan,
# switched from EST to CST/CDT in 1973.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER
Rule Menominee 1946 only - Apr lastSun 2:00 1:00 D
Rule Menominee 1946 only - Sep lastSun 2:00 0 S
Rule Menominee 1966 only - Apr lastSun 2:00 1:00 D
Rule Menominee 1966 only - Oct lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Menominee -5:50:27 - LMT 1885 Sep 18 12:00
-6:00 US C%sT 1946
-6:00 Menominee C%sT 1969 Apr 27 2:00
-5:00 - EST 1973 Apr 29 2:00
-6:00 US C%sT
# Navassa
# administered by the US Fish and Wildlife Service
# claimed by US under the provisions of the 1856 Guano Islands Act
# also claimed by Haiti
# occupied 1857/1900 by the Navassa Phosphate Co
# US lighthouse 1917/1996-09
# currently uninhabited
# see Mark Fineman, "An Isle Rich in Guano and Discord",
# _Los Angeles Times_ (1998-11-10), A1, A10; it cites
# Jimmy Skaggs, _The Great Guano Rush_ (1994).
################################################################################
# From Paul Eggert (2017-02-10):
#
# Unless otherwise specified, the source for data through 1990 is:
# Thomas G. Shanks and Rique Pottenger, The International Atlas (6th edition),
# San Diego: ACS Publications, Inc. (2003).
# Unfortunately this book contains many errors and cites no sources.
#
# Many years ago Gwillim Law wrote that a good source
# for time zone data was the International Air Transport
# Association's Standard Schedules Information Manual (IATA SSIM),
# published semiannually. Law sent in several helpful summaries
# of the IATA's data after 1990. Except where otherwise noted,
# IATA SSIM is the source for entries after 1990.
#
# Other sources occasionally used include:
#
# Edward W. Whitman, World Time Differences,
# Whitman Publishing Co, 2 Niagara Av, Ealing, London (undated),
# which I found in the UCLA library.
#
# William Willett, The Waste of Daylight, 19th edition
# <http://cs.ucla.edu/~eggert/The-Waste-of-Daylight-19th.pdf>
# [PDF] (1914-03)
#
# Milne J. Civil time. Geogr J. 1899 Feb;13(2):173-94
# <https://www.jstor.org/stable/1774359>.
#
# See the 'europe' file for Greenland.
# Canada
# From Alain LaBonté (1994-11-14):
# I post here the time zone abbreviations standardized in Canada
# for both English and French in the CAN/CSA-Z234.4-89 standard....
#
# UTC Standard time Daylight saving time
# offset French English French English
# -2:30 - - HAT NDT
# -3 - - HAA ADT
# -3:30 HNT NST - -
# -4 HNA AST HAE EDT
# -5 HNE EST HAC CDT
# -6 HNC CST HAR MDT
# -7 HNR MST HAP PDT
# -8 HNP PST HAY YDT
# -9 HNY YST - -
#
# HN: Heure Normale ST: Standard Time
# HA: Heure Avancée DT: Daylight saving Time
#
# A: de l'Atlantique Atlantic
# C: du Centre Central
# E: de l'Est Eastern
# M: Mountain
# N: Newfoundland
# P: du Pacifique Pacific
# R: des Rocheuses
# T: de Terre-Neuve
# Y: du Yukon Yukon
#
# From Paul Eggert (1994-11-22):
# Alas, this sort of thing must be handled by localization software.
# Unless otherwise specified, the data entries for Canada are all from Shanks
# & Pottenger.
# From Chris Walton (2006-04-01, 2006-04-25, 2006-06-26, 2007-01-31,
# 2007-03-01):
# The British Columbia government announced yesterday that it will
# adjust daylight savings next year to align with changes in the
# U.S. and the rest of Canada....
# https://archive.news.gov.bc.ca/releases/news_releases_2005-2009/2006AG0014-000330.htm
# ...
# Nova Scotia
# Daylight saving time will be extended by four weeks starting in 2007....
# https://www.novascotia.ca/just/regulations/rg2/2006/ma1206.pdf
#
# [For New Brunswick] the new legislation dictates that the time change is to
# be done at 02:00 instead of 00:01.
# https://www.gnb.ca/0062/acts/BBA-2006/Chap-19.pdf
# ...
# Manitoba has traditionally changed the clock every fall at 03:00.
# As of 2006, the transition is to take place one hour earlier at 02:00.
# https://web2.gov.mb.ca/laws/statutes/ccsm/o030e.php
# ...
# [Alberta, Ontario, Quebec] will follow US rules.
# http://www.qp.gov.ab.ca/documents/spring/CH03_06.CFM
# http://www.e-laws.gov.on.ca/DBLaws/Source/Regs/English/2006/R06111_e.htm
# http://www2.publicationsduquebec.gouv.qc.ca/dynamicSearch/telecharge.php?type=5&file=2006C39A.PDF
# ...
# P.E.I. will follow US rules....
# http://www.assembly.pe.ca/bills/pdf_chapter/62/3/chapter-41.pdf
# ...
# Province of Newfoundland and Labrador....
# http://www.hoa.gov.nl.ca/hoa/bills/Bill0634.htm
# ...
# Yukon
# https://www.gov.yk.ca/legislation/regs/oic2006_127.pdf
# ...
# N.W.T. will follow US rules. Whoever maintains the government web site
# does not seem to believe in bookmarks. To see the news release, click the
# following link and search for "Daylight Savings Time Change". Press the
# "Daylight Savings Time Change" link; it will fire off a popup using
# JavaScript.
# http://www.exec.gov.nt.ca/currentnews/currentPR.asp?mode=archive
# ...
# Nunavut
# An amendment to the Interpretation Act was registered on February 19/2007....
# http://action.attavik.ca/home/justice-gn/attach/2007/gaz02part2.pdf
# From Paul Eggert (2014-10-18):
# H. David Matthews and Mary Vincent's map
# "It's about TIME", _Canadian Geographic_ (September-October 1998)
# http://www.canadiangeographic.ca/Magazine/SO98/alacarte.asp
# contains detailed boundaries for regions observing nonstandard
# time and daylight saving time arrangements in Canada circa 1998.
#
# National Research Council Canada maintains info about time zones and DST.
# https://www.nrc-cnrc.gc.ca/eng/services/time/time_zones.html
# https://www.nrc-cnrc.gc.ca/eng/services/time/faq/index.html#Q5
# Its unofficial information is often taken from Matthews and Vincent.
# From Paul Eggert (2006-06-27):
# For now, assume all of DST-observing Canada will fall into line with the
# new US DST rules,
# From Chris Walton (2011-12-01)
# In the first of Tammy Hardwick's articles
# http://www.ilovecreston.com/?p=articles&t=spec&ar=260
# she quotes the Friday November 1/1918 edition of the Creston Review.
# The quote includes these two statements:
# 'Sunday the CPR went back to the old system of time...'
# '... The daylight saving scheme was dropped all over Canada at the same time,'
# These statements refer to a transition from daylight time to standard time
# that occurred nationally on Sunday October 27/1918. This transition was
# also documented in the Saturday October 26/1918 edition of the Toronto Star.
# In light of that evidence, we alter the date from the earlier believed
# Oct 31, to Oct 27, 1918 (and Sunday is a more likely transition day
# than Thursday) in all Canadian rulesets.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Canada 1918 only - Apr 14 2:00 1:00 D
Rule Canada 1918 only - Oct 27 2:00 0 S
Rule Canada 1942 only - Feb 9 2:00 1:00 W # War
Rule Canada 1945 only - Aug 14 23:00u 1:00 P # Peace
Rule Canada 1945 only - Sep 30 2:00 0 S
Rule Canada 1974 1986 - Apr lastSun 2:00 1:00 D
Rule Canada 1974 2006 - Oct lastSun 2:00 0 S
Rule Canada 1987 2006 - Apr Sun>=1 2:00 1:00 D
Rule Canada 2007 max - Mar Sun>=8 2:00 1:00 D
Rule Canada 2007 max - Nov Sun>=1 2:00 0 S
# Newfoundland and Labrador
# From Paul Eggert (2017-10-14):
# Legally Labrador should observe Newfoundland time; see:
# McLeod J. Labrador time - legal or not? St. John's Telegram, 2017-10-07
# http://www.thetelegram.com/news/local/labrador-time--legal-or-not-154860/
# Matthews and Vincent (1998) write that the only part of Labrador
# that follows the rules is the southeast corner, including Port Hope
# Simpson and Mary's Harbour, but excluding, say, Black Tickle.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule StJohns 1917 only - Apr 8 2:00 1:00 D
Rule StJohns 1917 only - Sep 17 2:00 0 S
# Whitman gives 1919 Apr 5 and 1920 Apr 5; go with Shanks & Pottenger.
Rule StJohns 1919 only - May 5 23:00 1:00 D
Rule StJohns 1919 only - Aug 12 23:00 0 S
# For 1931-1935 Whitman gives Apr same date; go with Shanks & Pottenger.
Rule StJohns 1920 1935 - May Sun>=1 23:00 1:00 D
Rule StJohns 1920 1935 - Oct lastSun 23:00 0 S
# For 1936-1941 Whitman gives May Sun>=8 and Oct Sun>=1; go with Shanks &
# Pottenger.
Rule StJohns 1936 1941 - May Mon>=9 0:00 1:00 D
Rule StJohns 1936 1941 - Oct Mon>=2 0:00 0 S
# Whitman gives the following transitions:
# 1942 03-01/12-31, 1943 05-30/09-05, 1944 07-10/09-02, 1945 01-01/10-07
# but go with Shanks & Pottenger and assume they used Canadian rules.
# For 1946-9 Whitman gives May 5,4,9,1 - Oct 1,5,3,2, and for 1950 he gives
# Apr 30 - Sep 24; go with Shanks & Pottenger.
Rule StJohns 1946 1950 - May Sun>=8 2:00 1:00 D
Rule StJohns 1946 1950 - Oct Sun>=2 2:00 0 S
Rule StJohns 1951 1986 - Apr lastSun 2:00 1:00 D
Rule StJohns 1951 1959 - Sep lastSun 2:00 0 S
Rule StJohns 1960 1986 - Oct lastSun 2:00 0 S
# From Paul Eggert (2000-10-02):
# INMS (2000-09-12) says that, since 1988 at least, Newfoundland switches
# at 00:01 local time. For now, assume it started in 1987.
# From Michael Pelley (2011-09-12):
# We received today, Monday, September 12, 2011, notification that the
# changes to the Newfoundland Standard Time Act have been proclaimed.
# The change in the Act stipulates that the change from Daylight Savings
# Time to Standard Time and from Standard Time to Daylight Savings Time
# now occurs at 2:00AM.
# ...
# http://www.assembly.nl.ca/legislation/sr/annualstatutes/2011/1106.chp.htm
# ...
# MICHAEL PELLEY | Manager of Enterprise Architecture - Solution Delivery
# Office of the Chief Information Officer
# Executive Council
# Government of Newfoundland & Labrador
Rule StJohns 1987 only - Apr Sun>=1 0:01 1:00 D
Rule StJohns 1987 2006 - Oct lastSun 0:01 0 S
Rule StJohns 1988 only - Apr Sun>=1 0:01 2:00 DD
Rule StJohns 1989 2006 - Apr Sun>=1 0:01 1:00 D
Rule StJohns 2007 2011 - Mar Sun>=8 0:01 1:00 D
Rule StJohns 2007 2010 - Nov Sun>=1 0:01 0 S
#
# St John's has an apostrophe, but Posix file names can't have apostrophes.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/St_Johns -3:30:52 - LMT 1884
-3:30:52 StJohns N%sT 1918
-3:30:52 Canada N%sT 1919
-3:30:52 StJohns N%sT 1935 Mar 30
-3:30 StJohns N%sT 1942 May 11
-3:30 Canada N%sT 1946
-3:30 StJohns N%sT 2011 Nov
-3:30 Canada N%sT
# most of east Labrador
# The name 'Happy Valley-Goose Bay' is too long; use 'Goose Bay'.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Goose_Bay -4:01:40 - LMT 1884 # Happy Valley-Goose Bay
-3:30:52 - NST 1918
-3:30:52 Canada N%sT 1919
-3:30:52 - NST 1935 Mar 30
-3:30 - NST 1936
-3:30 StJohns N%sT 1942 May 11
-3:30 Canada N%sT 1946
-3:30 StJohns N%sT 1966 Mar 15 2:00
-4:00 StJohns A%sT 2011 Nov
-4:00 Canada A%sT
# west Labrador, Nova Scotia, Prince Edward I
# From Brian Inglis (2015-07-20):
# From the historical weather station records available at:
# https://weatherspark.com/history/28351/1971/Sydney-Nova-Scotia-Canada
# Sydney shares the same time history as Glace Bay, so was
# likely to be the same across the island....
# Sydney, as the capital and most populous location, or Cape Breton, would
# have been better names for the zone had we known this in 1996.
# From Paul Eggert (2015-07-20):
# Shanks & Pottenger write that since 1970 most of this region has been like
# Halifax. Many locales did not observe peacetime DST until 1972;
# the Cape Breton area, represented by Glace Bay, is the largest we know of
# (Glace Bay was perhaps not the best name choice but no point changing now).
# Shanks & Pottenger also write that Liverpool, NS was the only town
# in Canada to observe DST in 1971 but not 1970; for now we'll assume
# this is a typo.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Halifax 1916 only - Apr 1 0:00 1:00 D
Rule Halifax 1916 only - Oct 1 0:00 0 S
Rule Halifax 1920 only - May 9 0:00 1:00 D
Rule Halifax 1920 only - Aug 29 0:00 0 S
Rule Halifax 1921 only - May 6 0:00 1:00 D
Rule Halifax 1921 1922 - Sep 5 0:00 0 S
Rule Halifax 1922 only - Apr 30 0:00 1:00 D
Rule Halifax 1923 1925 - May Sun>=1 0:00 1:00 D
Rule Halifax 1923 only - Sep 4 0:00 0 S
Rule Halifax 1924 only - Sep 15 0:00 0 S
Rule Halifax 1925 only - Sep 28 0:00 0 S
Rule Halifax 1926 only - May 16 0:00 1:00 D
Rule Halifax 1926 only - Sep 13 0:00 0 S
Rule Halifax 1927 only - May 1 0:00 1:00 D
Rule Halifax 1927 only - Sep 26 0:00 0 S
Rule Halifax 1928 1931 - May Sun>=8 0:00 1:00 D
Rule Halifax 1928 only - Sep 9 0:00 0 S
Rule Halifax 1929 only - Sep 3 0:00 0 S
Rule Halifax 1930 only - Sep 15 0:00 0 S
Rule Halifax 1931 1932 - Sep Mon>=24 0:00 0 S
Rule Halifax 1932 only - May 1 0:00 1:00 D
Rule Halifax 1933 only - Apr 30 0:00 1:00 D
Rule Halifax 1933 only - Oct 2 0:00 0 S
Rule Halifax 1934 only - May 20 0:00 1:00 D
Rule Halifax 1934 only - Sep 16 0:00 0 S
Rule Halifax 1935 only - Jun 2 0:00 1:00 D
Rule Halifax 1935 only - Sep 30 0:00 0 S
Rule Halifax 1936 only - Jun 1 0:00 1:00 D
Rule Halifax 1936 only - Sep 14 0:00 0 S
Rule Halifax 1937 1938 - May Sun>=1 0:00 1:00 D
Rule Halifax 1937 1941 - Sep Mon>=24 0:00 0 S
Rule Halifax 1939 only - May 28 0:00 1:00 D
Rule Halifax 1940 1941 - May Sun>=1 0:00 1:00 D
Rule Halifax 1946 1949 - Apr lastSun 2:00 1:00 D
Rule Halifax 1946 1949 - Sep lastSun 2:00 0 S
Rule Halifax 1951 1954 - Apr lastSun 2:00 1:00 D
Rule Halifax 1951 1954 - Sep lastSun 2:00 0 S
Rule Halifax 1956 1959 - Apr lastSun 2:00 1:00 D
Rule Halifax 1956 1959 - Sep lastSun 2:00 0 S
Rule Halifax 1962 1973 - Apr lastSun 2:00 1:00 D
Rule Halifax 1962 1973 - Oct lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Halifax -4:14:24 - LMT 1902 Jun 15
-4:00 Halifax A%sT 1918
-4:00 Canada A%sT 1919
-4:00 Halifax A%sT 1942 Feb 9 2:00s
-4:00 Canada A%sT 1946
-4:00 Halifax A%sT 1974
-4:00 Canada A%sT
Zone America/Glace_Bay -3:59:48 - LMT 1902 Jun 15
-4:00 Canada A%sT 1953
-4:00 Halifax A%sT 1954
-4:00 - AST 1972
-4:00 Halifax A%sT 1974
-4:00 Canada A%sT
# New Brunswick
# From Paul Eggert (2007-01-31):
# The Time Definition Act <http://www.gnb.ca/0062/PDF-acts/t-06.pdf>
# says they changed at 00:01 through 2006, and
# <http://www.canlii.org/nb/laws/sta/t-6/20030127/whole.html> makes it
# clear that this was the case since at least 1993.
# For now, assume it started in 1993.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Moncton 1933 1935 - Jun Sun>=8 1:00 1:00 D
Rule Moncton 1933 1935 - Sep Sun>=8 1:00 0 S
Rule Moncton 1936 1938 - Jun Sun>=1 1:00 1:00 D
Rule Moncton 1936 1938 - Sep Sun>=1 1:00 0 S
Rule Moncton 1939 only - May 27 1:00 1:00 D
Rule Moncton 1939 1941 - Sep Sat>=21 1:00 0 S
Rule Moncton 1940 only - May 19 1:00 1:00 D
Rule Moncton 1941 only - May 4 1:00 1:00 D
Rule Moncton 1946 1972 - Apr lastSun 2:00 1:00 D
Rule Moncton 1946 1956 - Sep lastSun 2:00 0 S
Rule Moncton 1957 1972 - Oct lastSun 2:00 0 S
Rule Moncton 1993 2006 - Apr Sun>=1 0:01 1:00 D
Rule Moncton 1993 2006 - Oct lastSun 0:01 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Moncton -4:19:08 - LMT 1883 Dec 9
-5:00 - EST 1902 Jun 15
-4:00 Canada A%sT 1933
-4:00 Moncton A%sT 1942
-4:00 Canada A%sT 1946
-4:00 Moncton A%sT 1973
-4:00 Canada A%sT 1993
-4:00 Moncton A%sT 2007
-4:00 Canada A%sT
# Quebec
# From Paul Eggert (2015-03-24):
# See America/Toronto for most of Quebec, including Montreal.
#
# Matthews and Vincent (1998) also write that Quebec east of the -63
# meridian is supposed to observe AST, but residents as far east as
# Natashquan use EST/EDT, and residents east of Natashquan use AST.
# The Quebec department of justice writes in
# "The situation in Minganie and Basse-Côte-Nord"
# http://www.justice.gouv.qc.ca/english/publications/generale/temps-minganie-a.htm
# that the coastal strip from just east of Natashquan to Blanc-Sablon
# observes Atlantic standard time all year round.
# https://www.assnat.qc.ca/Media/Process.aspx?MediaId=ANQ.Vigie.Bll.DocumentGenerique_8845en
# says this common practice was codified into law as of 2007.
# For lack of better info, guess this practice began around 1970, contra to
# Shanks & Pottenger who have this region observing AST/ADT.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Blanc-Sablon -3:48:28 - LMT 1884
-4:00 Canada A%sT 1970
-4:00 - AST
# Ontario
# From Paul Eggert (2006-07-09):
# Shanks & Pottenger write that since 1970 most of Ontario has been like
# Toronto.
# Thunder Bay skipped DST in 1973.
# Many smaller locales did not observe peacetime DST until 1974;
# Nipigon (EST) and Rainy River (CST) are the largest that we know of.
# Far west Ontario is like Winnipeg; far east Quebec is like Halifax.
# From Mark Brader (2003-07-26):
# [According to the Toronto Star] Orillia, Ontario, adopted DST
# effective Saturday, 1912-06-22, 22:00; the article mentions that
# Port Arthur (now part of Thunder Bay, Ontario) as well as Moose Jaw
# have already done so. In Orillia DST was to run until Saturday,
# 1912-08-31 (no time mentioned), but it was met with considerable
# hostility from certain segments of the public, and was revoked after
# only two weeks - I copied it as Saturday, 1912-07-07, 22:00, but
# presumably that should be -07-06. (1912-06-19, -07-12; also letters
# earlier in June).
#
# Kenora, Ontario, was to abandon DST on 1914-06-01 (-05-21).
#
# From Paul Eggert (2017-07-08):
# For more on Orillia, see: Daubs K. Bold attempt at daylight saving
# time became a comic failure in Orillia. Toronto Star 2017-07-08.
# https://www.thestar.com/news/insight/2017/07/08/bold-attempt-at-daylight-saving-time-became-a-comic-failure-in-orillia.html
# From Paul Eggert (1997-10-17):
# Mark Brader writes that an article in the 1997-10-14 Toronto Star
# says that Atikokan, Ontario currently does not observe DST,
# but will vote on 11-10 whether to use EST/EDT.
# He also writes that the Ontario Time Act (1990, Chapter T.9)
# http://www.gov.on.ca/MBS/english/publications/statregs/conttext.html
# says that Ontario east of 90W uses EST/EDT, and west of 90W uses CST/CDT.
# Officially Atikokan is therefore on CST/CDT, and most likely this report
# concerns a non-official time observed as a matter of local practice.
#
# From Paul Eggert (2000-10-02):
# Matthews and Vincent (1998) write that Atikokan, Pickle Lake, and
# New Osnaburgh observe CST all year, that Big Trout Lake observes
# CST/CDT, and that Upsala and Shebandowan observe EST/EDT, all in
# violation of the official Ontario rules.
#
# From Paul Eggert (2006-07-09):
# Chris Walton (2006-07-06) mentioned an article by Stephanie MacLellan in the
# 2005-07-21 Chronicle-Journal, which said:
#
# The clocks in Atikokan stay set on standard time year-round.
# This means they spend about half the time on central time and
# the other half on eastern time.
#
# For the most part, the system works, Mayor Dennis Brown said.
#
# "The majority of businesses in Atikokan deal more with Eastern
# Canada, but there are some that deal with Western Canada," he
# said. "I don't see any changes happening here."
#
# Walton also writes "Supposedly Pickle Lake and Mishkeegogamang
# [New Osnaburgh] follow the same practice."
# From Garry McKinnon (2006-07-14) via Chris Walton:
# I chatted with a member of my board who has an outstanding memory
# and a long history in Atikokan (and in the telecom industry) and he
# can say for certain that Atikokan has been practicing the current
# time keeping since 1952, at least.
# From Paul Eggert (2006-07-17):
# Shanks & Pottenger say that Atikokan has agreed with Rainy River
# ever since standard time was introduced, but the information from
# McKinnon sounds more authoritative. For now, assume that Atikokan
# switched to EST immediately after WWII era daylight saving time
# ended. This matches the old (less-populous) America/Coral_Harbour
# entry since our cutoff date of 1970, so we can move
# America/Coral_Harbour to the 'backward' file.
# From Mark Brader (2010-03-06):
#
# Currently the database has:
#
# # Ontario
#
# # From Paul Eggert (2006-07-09):
# # Shanks & Pottenger write that since 1970 most of Ontario has been like
# # Toronto.
# # Thunder Bay skipped DST in 1973.
# # Many smaller locales did not observe peacetime DST until 1974;
# # Nipigon (EST) and Rainy River (CST) are the largest that we know of.
#
# In the (Toronto) Globe and Mail for Saturday, 1955-09-24, in the bottom
# right corner of page 1, it says that Toronto will return to standard
# time at 2 am Sunday morning (which agrees with the database), and that:
#
# The one-hour setback will go into effect throughout most of Ontario,
# except in areas like Windsor which remains on standard time all year.
#
# Windsor is, of course, a lot larger than Nipigon.
#
# I only came across this incidentally. I don't know if Windsor began
# observing DST when Detroit did, or in 1974, or on some other date.
#
# By the way, the article continues by noting that:
#
# Some cities in the United States have pushed the deadline back
# three weeks and will change over from daylight saving in October.
# From Arthur David Olson (2010-07-17):
#
# "Standard Time and Time Zones in Canada" appeared in
# The Journal of The Royal Astronomical Society of Canada,
# volume 26, number 2 (February 1932) and, as of 2010-07-17,
# was available at
# http://adsabs.harvard.edu/full/1932JRASC..26...49S
#
# It includes the text below (starting on page 57):
#
# A list of the places in Canada using daylight saving time would
# require yearly revision. From information kindly furnished by
# the provincial governments and by the postmasters in many cities
# and towns, it is found that the following places used daylight sav-
# ing in 1930. The information for the province of Quebec is definite,
# for the other provinces only approximate:
#
# Province Daylight saving time used
# Prince Edward Island Not used.
# Nova Scotia In Halifax only.
# New Brunswick In St. John only.
# Quebec In the following places:
# Montreal Lachine
# Quebec Mont-Royal
# Lévis Iberville
# St. Lambert Cap de la Madelèine
# Verdun Loretteville
# Westmount Richmond
# Outremont St. Jérôme
# Longueuil Greenfield Park
# Arvida Waterloo
# Chambly-Canton Beaulieu
# Melbourne La Tuque
# St. Théophile Buckingham
# Ontario Used generally in the cities and towns along
# the southerly part of the province. Not
# used in the northwesterly part.
# Manitoba Not used.
# Saskatchewan In Regina only.
# Alberta Not used.
# British Columbia Not used.
#
# With some exceptions, the use of daylight saving may be said to be limited
# to those cities and towns lying between Quebec city and Windsor, Ont.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Toronto 1919 only - Mar 30 23:30 1:00 D
Rule Toronto 1919 only - Oct 26 0:00 0 S
Rule Toronto 1920 only - May 2 2:00 1:00 D
Rule Toronto 1920 only - Sep 26 0:00 0 S
Rule Toronto 1921 only - May 15 2:00 1:00 D
Rule Toronto 1921 only - Sep 15 2:00 0 S
Rule Toronto 1922 1923 - May Sun>=8 2:00 1:00 D
# Shanks & Pottenger say 1923-09-19; assume it's a typo and that "-16"
# was meant.
Rule Toronto 1922 1926 - Sep Sun>=15 2:00 0 S
Rule Toronto 1924 1927 - May Sun>=1 2:00 1:00 D
# The 1927-to-1939 rules can be expressed more simply as
# Rule Toronto 1927 1937 - Sep Sun>=25 2:00 0 S
# Rule Toronto 1928 1937 - Apr Sun>=25 2:00 1:00 D
# Rule Toronto 1938 1940 - Apr lastSun 2:00 1:00 D
# Rule Toronto 1938 1939 - Sep lastSun 2:00 0 S
# The rules below avoid use of Sun>=25
# (which pre-2004 versions of zic cannot handle).
Rule Toronto 1927 1932 - Sep lastSun 2:00 0 S
Rule Toronto 1928 1931 - Apr lastSun 2:00 1:00 D
Rule Toronto 1932 only - May 1 2:00 1:00 D
Rule Toronto 1933 1940 - Apr lastSun 2:00 1:00 D
Rule Toronto 1933 only - Oct 1 2:00 0 S
Rule Toronto 1934 1939 - Sep lastSun 2:00 0 S
Rule Toronto 1945 1946 - Sep lastSun 2:00 0 S
Rule Toronto 1946 only - Apr lastSun 2:00 1:00 D
Rule Toronto 1947 1949 - Apr lastSun 0:00 1:00 D
Rule Toronto 1947 1948 - Sep lastSun 0:00 0 S
Rule Toronto 1949 only - Nov lastSun 0:00 0 S
Rule Toronto 1950 1973 - Apr lastSun 2:00 1:00 D
Rule Toronto 1950 only - Nov lastSun 2:00 0 S
Rule Toronto 1951 1956 - Sep lastSun 2:00 0 S
# Shanks & Pottenger say Toronto ended DST a week early in 1971,
# namely on 1971-10-24, but Mark Brader wrote (2003-05-31) that this
# is wrong, and that he had confirmed it by checking the 1971-10-30
# Toronto Star, which said that DST was ending 1971-10-31 as usual.
Rule Toronto 1957 1973 - Oct lastSun 2:00 0 S
# From Paul Eggert (2003-07-27):
# Willett (1914-03) writes (p. 17) "In the Cities of Fort William, and
# Port Arthur, Ontario, the principle of the Bill has been in
# operation for the past three years, and in the City of Moose Jaw,
# Saskatchewan, for one year."
# From David Bryan via Tory Tronrud, Director/Curator,
# Thunder Bay Museum (2003-11-12):
# There is some suggestion, however, that, by-law or not, daylight
# savings time was being practiced in Fort William and Port Arthur
# before 1909.... [I]n 1910, the line between the Eastern and Central
# Time Zones was permanently moved about two hundred miles west to
# include the Thunder Bay area.... When Canada adopted daylight
# savings time in 1916, Fort William and Port Arthur, having done so
# already, did not change their clocks.... During the Second World
# War,... [t]he cities agreed to implement DST during the summer
# months for the remainder of the war years.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Toronto -5:17:32 - LMT 1895
-5:00 Canada E%sT 1919
-5:00 Toronto E%sT 1942 Feb 9 2:00s
-5:00 Canada E%sT 1946
-5:00 Toronto E%sT 1974
-5:00 Canada E%sT
Zone America/Thunder_Bay -5:57:00 - LMT 1895
-6:00 - CST 1910
-5:00 - EST 1942
-5:00 Canada E%sT 1970
-5:00 Toronto E%sT 1973
-5:00 - EST 1974
-5:00 Canada E%sT
Zone America/Nipigon -5:53:04 - LMT 1895
-5:00 Canada E%sT 1940 Sep 29
-5:00 1:00 EDT 1942 Feb 9 2:00s
-5:00 Canada E%sT
Zone America/Rainy_River -6:18:16 - LMT 1895
-6:00 Canada C%sT 1940 Sep 29
-6:00 1:00 CDT 1942 Feb 9 2:00s
-6:00 Canada C%sT
Zone America/Atikokan -6:06:28 - LMT 1895
-6:00 Canada C%sT 1940 Sep 29
-6:00 1:00 CDT 1942 Feb 9 2:00s
-6:00 Canada C%sT 1945 Sep 30 2:00
-5:00 - EST
# Manitoba
# From Rob Douglas (2006-04-06):
# the old Manitoba Time Act - as amended by Bill 2, assented to
# March 27, 1987 ... said ...
# "between two o'clock Central Standard Time in the morning of
# the first Sunday of April of each year and two o'clock Central
# Standard Time in the morning of the last Sunday of October next
# following, one hour in advance of Central Standard Time."...
# I believe that the English legislation [of the old time act] had
# been assented to (March 22, 1967)....
# Also, as far as I can tell, there was no order-in-council varying
# the time of Daylight Saving Time for 2005 and so the provisions of
# the 1987 version would apply - the changeover was at 2:00 Central
# Standard Time (i.e. not until 3:00 Central Daylight Time).
# From Paul Eggert (2006-04-10):
# Shanks & Pottenger say Manitoba switched at 02:00 (not 02:00s)
# starting 1966. Since 02:00s is clearly correct for 1967 on, assume
# it was also 02:00s in 1966.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Winn 1916 only - Apr 23 0:00 1:00 D
Rule Winn 1916 only - Sep 17 0:00 0 S
Rule Winn 1918 only - Apr 14 2:00 1:00 D
Rule Winn 1918 only - Oct 27 2:00 0 S
Rule Winn 1937 only - May 16 2:00 1:00 D
Rule Winn 1937 only - Sep 26 2:00 0 S
Rule Winn 1942 only - Feb 9 2:00 1:00 W # War
Rule Winn 1945 only - Aug 14 23:00u 1:00 P # Peace
Rule Winn 1945 only - Sep lastSun 2:00 0 S
Rule Winn 1946 only - May 12 2:00 1:00 D
Rule Winn 1946 only - Oct 13 2:00 0 S
Rule Winn 1947 1949 - Apr lastSun 2:00 1:00 D
Rule Winn 1947 1949 - Sep lastSun 2:00 0 S
Rule Winn 1950 only - May 1 2:00 1:00 D
Rule Winn 1950 only - Sep 30 2:00 0 S
Rule Winn 1951 1960 - Apr lastSun 2:00 1:00 D
Rule Winn 1951 1958 - Sep lastSun 2:00 0 S
Rule Winn 1959 only - Oct lastSun 2:00 0 S
Rule Winn 1960 only - Sep lastSun 2:00 0 S
Rule Winn 1963 only - Apr lastSun 2:00 1:00 D
Rule Winn 1963 only - Sep 22 2:00 0 S
Rule Winn 1966 1986 - Apr lastSun 2:00s 1:00 D
Rule Winn 1966 2005 - Oct lastSun 2:00s 0 S
Rule Winn 1987 2005 - Apr Sun>=1 2:00s 1:00 D
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Winnipeg -6:28:36 - LMT 1887 Jul 16
-6:00 Winn C%sT 2006
-6:00 Canada C%sT
# Saskatchewan
# From Mark Brader (2003-07-26):
# The first actual adoption of DST in Canada was at the municipal
# level. As the [Toronto] Star put it (1912-06-07), "While people
# elsewhere have long been talking of legislation to save daylight,
# the city of Moose Jaw [Saskatchewan] has acted on its own hook."
# DST in Moose Jaw began on Saturday, 1912-06-01 (no time mentioned:
# presumably late evening, as below), and would run until "the end of
# the summer". The discrepancy between municipal time and railroad
# time was noted.
# From Paul Eggert (2003-07-27):
# Willett (1914-03) notes that DST "has been in operation ... in the
# City of Moose Jaw, Saskatchewan, for one year."
# From Paul Eggert (2006-03-22):
# Shanks & Pottenger say that since 1970 this region has mostly been as Regina.
# Some western towns (e.g. Swift Current) switched from MST/MDT to CST in 1972.
# Other western towns (e.g. Lloydminster) are like Edmonton.
# Matthews and Vincent (1998) write that Denare Beach and Creighton
# are like Winnipeg, in violation of Saskatchewan law.
# From W. Jones (1992-11-06):
# The. . .below is based on information I got from our law library, the
# provincial archives, and the provincial Community Services department.
# A precise history would require digging through newspaper archives, and
# since you didn't say what you wanted, I didn't bother.
#
# Saskatchewan is split by a time zone meridian (105W) and over the years
# the boundary became pretty ragged as communities near it reevaluated
# their affiliations in one direction or the other. In 1965 a provincial
# referendum favoured legislating common time practices.
#
# On 15 April 1966 the Time Act (c. T-14, Revised Statutes of
# Saskatchewan 1978) was proclaimed, and established that the eastern
# part of Saskatchewan would use CST year round, that districts in
# northwest Saskatchewan would by default follow CST but could opt to
# follow Mountain Time rules (thus 1 hour difference in the winter and
# zero in the summer), and that districts in southwest Saskatchewan would
# by default follow MT but could opt to follow CST.
#
# It took a few years for the dust to settle (I know one story of a town
# on one time zone having its school in another, such that a mom had to
# serve her family lunch in two shifts), but presently it seems that only
# a few towns on the border with Alberta (e.g. Lloydminster) follow MT
# rules any more; all other districts appear to have used CST year round
# since sometime in the 1960s.
# From Chris Walton (2006-06-26):
# The Saskatchewan time act which was last updated in 1996 is about 30 pages
# long and rather painful to read.
# http://www.qp.gov.sk.ca/documents/English/Statutes/Statutes/T14.pdf
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Regina 1918 only - Apr 14 2:00 1:00 D
Rule Regina 1918 only - Oct 27 2:00 0 S
Rule Regina 1930 1934 - May Sun>=1 0:00 1:00 D
Rule Regina 1930 1934 - Oct Sun>=1 0:00 0 S
Rule Regina 1937 1941 - Apr Sun>=8 0:00 1:00 D
Rule Regina 1937 only - Oct Sun>=8 0:00 0 S
Rule Regina 1938 only - Oct Sun>=1 0:00 0 S
Rule Regina 1939 1941 - Oct Sun>=8 0:00 0 S
Rule Regina 1942 only - Feb 9 2:00 1:00 W # War
Rule Regina 1945 only - Aug 14 23:00u 1:00 P # Peace
Rule Regina 1945 only - Sep lastSun 2:00 0 S
Rule Regina 1946 only - Apr Sun>=8 2:00 1:00 D
Rule Regina 1946 only - Oct Sun>=8 2:00 0 S
Rule Regina 1947 1957 - Apr lastSun 2:00 1:00 D
Rule Regina 1947 1957 - Sep lastSun 2:00 0 S
Rule Regina 1959 only - Apr lastSun 2:00 1:00 D
Rule Regina 1959 only - Oct lastSun 2:00 0 S
#
Rule Swift 1957 only - Apr lastSun 2:00 1:00 D
Rule Swift 1957 only - Oct lastSun 2:00 0 S
Rule Swift 1959 1961 - Apr lastSun 2:00 1:00 D
Rule Swift 1959 only - Oct lastSun 2:00 0 S
Rule Swift 1960 1961 - Sep lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Regina -6:58:36 - LMT 1905 Sep
-7:00 Regina M%sT 1960 Apr lastSun 2:00
-6:00 - CST
Zone America/Swift_Current -7:11:20 - LMT 1905 Sep
-7:00 Canada M%sT 1946 Apr lastSun 2:00
-7:00 Regina M%sT 1950
-7:00 Swift M%sT 1972 Apr lastSun 2:00
-6:00 - CST
# Alberta
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Edm 1918 1919 - Apr Sun>=8 2:00 1:00 D
Rule Edm 1918 only - Oct 27 2:00 0 S
Rule Edm 1919 only - May 27 2:00 0 S
Rule Edm 1920 1923 - Apr lastSun 2:00 1:00 D
Rule Edm 1920 only - Oct lastSun 2:00 0 S
Rule Edm 1921 1923 - Sep lastSun 2:00 0 S
Rule Edm 1942 only - Feb 9 2:00 1:00 W # War
Rule Edm 1945 only - Aug 14 23:00u 1:00 P # Peace
Rule Edm 1945 only - Sep lastSun 2:00 0 S
Rule Edm 1947 only - Apr lastSun 2:00 1:00 D
Rule Edm 1947 only - Sep lastSun 2:00 0 S
Rule Edm 1967 only - Apr lastSun 2:00 1:00 D
Rule Edm 1967 only - Oct lastSun 2:00 0 S
Rule Edm 1969 only - Apr lastSun 2:00 1:00 D
Rule Edm 1969 only - Oct lastSun 2:00 0 S
Rule Edm 1972 1986 - Apr lastSun 2:00 1:00 D
Rule Edm 1972 2006 - Oct lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Edmonton -7:33:52 - LMT 1906 Sep
-7:00 Edm M%sT 1987
-7:00 Canada M%sT
# British Columbia
# From Paul Eggert (2006-03-22):
# Shanks & Pottenger write that since 1970 most of this region has
# been like Vancouver.
# Dawson Creek uses MST. Much of east BC is like Edmonton.
# Matthews and Vincent (1998) write that Creston is like Dawson Creek.
# It seems though that (re: Creston) is not entirely correct:
# From Chris Walton (2011-12-01):
# There are two areas within the Canadian province of British Columbia
# that do not currently observe daylight saving:
# a) The Creston Valley (includes the town of Creston and surrounding area)
# b) The eastern half of the Peace River Regional District
# (includes the cities of Dawson Creek and Fort St. John)
# Earlier this year I stumbled across a detailed article about the time
# keeping history of Creston; it was written by Tammy Hardwick who is the
# manager of the Creston & District Museum. The article was written in May 2009.
# http://www.ilovecreston.com/?p=articles&t=spec&ar=260
# According to the article, Creston has not changed its clocks since June 1918.
# i.e. Creston has been stuck on UT-7 for 93 years.
# Dawson Creek, on the other hand, changed its clocks as recently as April 1972.
# Unfortunately the exact date for the time change in June 1918 remains
# unknown and will be difficult to ascertain. I e-mailed Tammy a few months
# ago to ask if Sunday June 2 was a reasonable guess. She said it was just
# as plausible as any other date (in June). She also said that after writing
# the article she had discovered another time change in 1916; this is the
# subject of another article which she wrote in October 2010.
# http://www.creston.museum.bc.ca/index.php?module=comments&uop=view_comment&cm+id=56
# Here is a summary of the three clock change events in Creston's history:
# 1. 1884 or 1885: adoption of Mountain Standard Time (GMT-7)
# Exact date unknown
# 2. Oct 1916: switch to Pacific Standard Time (GMT-8)
# Exact date in October unknown; Sunday October 1 is a reasonable guess.
# 3. June 1918: switch to Pacific Daylight Time (GMT-7)
# Exact date in June unknown; Sunday June 2 is a reasonable guess.
# note 1:
# On Oct 27/1918 when daylight saving ended in the rest of Canada,
# Creston did not change its clocks.
# note 2:
# During WWII when the Federal Government legislated a mandatory clock change,
# Creston did not oblige.
# note 3:
# There is no guarantee that Creston will remain on Mountain Standard Time
# (UTC-7) forever.
# The subject was debated at least once this year by the town Council.
# http://www.bclocalnews.com/kootenay_rockies/crestonvalleyadvance/news/116760809.html
# During a period WWII, summer time (Daylight saying) was mandatory in Canada.
# In Creston, that was handled by shifting the area to PST (-8:00) then applying
# summer time to cause the offset to be -7:00, the same as it had been before
# the change. It can be argued that the timezone abbreviation during this
# period should be PDT rather than MST, but that doesn't seem important enough
# (to anyone) to further complicate the rules.
# The transition dates (and times) are guesses.
# From Matt Johnson (2015-09-21):
# Fort Nelson, BC, Canada will cancel DST this year. So while previously they
# were aligned with America/Vancouver, they're now aligned with
# America/Dawson_Creek.
# http://www.northernrockies.ca/EN/meta/news/archives/2015/northern-rockies-time-change.html
#
# From Tim Parenti (2015-09-23):
# This requires a new zone for the Northern Rockies Regional Municipality,
# America/Fort_Nelson. The resolution of 2014-12-08 was reached following a
# 2014-11-15 poll with nearly 75% support. Effectively, the municipality has
# been on MST (-0700) like Dawson Creek since it advanced its clocks on
# 2015-03-08.
#
# From Paul Eggert (2015-09-23):
# Shanks says Fort Nelson did not observe DST in 1946, unlike Vancouver.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Vanc 1918 only - Apr 14 2:00 1:00 D
Rule Vanc 1918 only - Oct 27 2:00 0 S
Rule Vanc 1942 only - Feb 9 2:00 1:00 W # War
Rule Vanc 1945 only - Aug 14 23:00u 1:00 P # Peace
Rule Vanc 1945 only - Sep 30 2:00 0 S
Rule Vanc 1946 1986 - Apr lastSun 2:00 1:00 D
Rule Vanc 1946 only - Oct 13 2:00 0 S
Rule Vanc 1947 1961 - Sep lastSun 2:00 0 S
Rule Vanc 1962 2006 - Oct lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Vancouver -8:12:28 - LMT 1884
-8:00 Vanc P%sT 1987
-8:00 Canada P%sT
Zone America/Dawson_Creek -8:00:56 - LMT 1884
-8:00 Canada P%sT 1947
-8:00 Vanc P%sT 1972 Aug 30 2:00
-7:00 - MST
Zone America/Fort_Nelson -8:10:47 - LMT 1884
-8:00 Vanc P%sT 1946
-8:00 - PST 1947
-8:00 Vanc P%sT 1987
-8:00 Canada P%sT 2015 Mar 8 2:00
-7:00 - MST
Zone America/Creston -7:46:04 - LMT 1884
-7:00 - MST 1916 Oct 1
-8:00 - PST 1918 Jun 2
-7:00 - MST
# Northwest Territories, Nunavut, Yukon
# From Paul Eggert (2006-03-22):
# Dawson switched to PST in 1973. Inuvik switched to MST in 1979.
# Mathew Englander (1996-10-07) gives the following refs:
# * 1967. Paragraph 28(34)(g) of the Interpretation Act, S.C. 1967-68,
# c. 7 defines Yukon standard time as UTC-9....
# see Interpretation Act, R.S.C. 1985, c. I-21, s. 35(1).
# [https://www.canlii.org/en/ca/laws/stat/rsc-1985-c-i-21/latest/rsc-1985-c-i-21.html]
# * C.O. 1973/214 switched Yukon to PST on 1973-10-28 00:00.
# * O.I.C. 1980/02 established DST.
# * O.I.C. 1987/056 changed DST to Apr firstSun 2:00 to Oct lastSun 2:00.
# From Brian Inglis (2015-04-14):
#
# I tried to trace the history of Yukon time and found the following
# regulations, giving the reference title and URL if found, regulation name,
# and relevant quote if available. Each regulation specifically revokes its
# predecessor. The final reference is to the current Interpretation Act
# authorizing and resulting from these regulatory changes.
#
# Only recent regulations were retrievable via Yukon government site search or
# index, and only some via Canadian legal sources. Other sources used include
# articles titled "Standard Time and Time Zones in Canada" from JRASC via ADS
# Abstracts, cited by ADO for 1932 ..., and updated versions from 1958 and
# 1970 quoted below; each article includes current extracts from provincial
# and territorial ST and DST regulations at the end, summaries and details of
# standard times and daylight saving time at many locations across Canada,
# with time zone maps, tables and calculations for Canadian Sunrise, Sunset,
# and LMST; they also cover many countries and global locations, with a chart
# and table showing current Universal Time offsets, and may be useful as
# another source of information for 1970 and earlier.
#
# * Standard Time and Time Zones in Canada; Smith, C.C.; JRASC, Vol. 26,
# pp.49-77; February 1932; SAO/NASA Astrophysics Data System (ADS)
# http://adsabs.harvard.edu/abs/1932JRASC..26...49S from p.75:
# Yukon Interpretation Ordinance
# Yukon standard time is the local mean time at the one hundred and
# thirty-fifth meridian.
#
# * Standard Time and Time Zones in Canada; Smith, C.C.; Thomson, Malcolm M.;
# JRASC, Vol. 52, pp.193-223; October 1958; SAO/NASA Astrophysics Data System
# (ADS) http://adsabs.harvard.edu/abs/1958JRASC..52..193S from pp.220-1:
# Yukon Interpretation Ordinance, 1955, Chap. 16.
#
# (1) Subject to this section, standard time shall be reckoned as nine
# hours behind Greenwich Time and called Yukon Standard Time.
#
# (2) Notwithstanding subsection (1), the Commissioner may make regulations
# varying the manner of reckoning standard time.
#
# * Yukon Territory Commissioner's Order 1966-20 Interpretation Ordinance
# http://? - no online source found
#
# * Standard Time and Time Zones in Canada; Thomson, Malcolm M.; JRASC,
# Vol. 64, pp.129-162; June 1970; SAO/NASA Astrophysics Data System (ADS)
# http://adsabs.harvard.edu/abs/1970JRASC..64..129T from p.156: Yukon
# Territory Commissioner's Order 1967-59 Interpretation Ordinance ...
#
# 1. Commissioner's Order 1966-20 dated at Whitehorse in the Yukon
# Territory on 27th January, 1966, is hereby revoked.
#
# 2. Yukon (East) Standard Time as defined by section 36 of the
# Interpretation Ordinance from and after mid-night on the 28th day of May,
# 1967 shall be reckoned in the same manner as Pacific Standard Time, that
# is to say, eight hours behind Greenwich Time in the area of the Yukon
# Territory lying east of the 138th degree longitude west.
#
# 3. In the remainder of the Territory, lying west of the 138th degree
# longitude west, Yukon (West) Standard Time shall be reckoned as nine
# hours behind Greenwich Time.
#
# * Yukon Standard Time defined as Pacific Standard Time, YCO 1973/214
# https://www.canlii.org/en/yk/laws/regu/yco-1973-214/latest/yco-1973-214.html
# C.O. 1973/214 INTERPRETATION ACT ...
#
# 1. Effective October 28, 1973 Commissioner's Order 1967/59 is hereby
# revoked.
#
# 2. Yukon Standard Time as defined by section 36 of the Interpretation
# Act from and after midnight on the twenty-eighth day of October, 1973
# shall be reckoned in the same manner as Pacific Standard Time, that is
# to say eight hours behind Greenwich Time.
#
# * O.I.C. 1980/02 INTERPRETATION ACT
# http://? - no online source found
#
# * Yukon Daylight Saving Time, YOIC 1987/56
# https://www.canlii.org/en/yk/laws/regu/yoic-1987-56/latest/yoic-1987-56.html
# O.I.C. 1987/056 INTERPRETATION ACT ...
#
# In every year between
# (a) two o'clock in the morning in the first Sunday in April, and
# (b) two o'clock in the morning in the last Sunday in October,
# Standard Time shall be reckoned as seven hours behind Greenwich Time and
# called Yukon Daylight Saving Time.
# ...
# Dated ... 9th day of March, A.D., 1987.
#
# * Yukon Daylight Saving Time 2006, YOIC 2006/127
# https://www.canlii.org/en/yk/laws/regu/yoic-2006-127/latest/yoic-2006-127.html
# O.I.C. 2006/127 INTERPRETATION ACT ...
#
# 1. In Yukon each year the time for general purposes shall be 7 hours
# behind Greenwich mean time during the period commencing at two o'clock
# in the forenoon on the second Sunday of March and ending at two o'clock
# in the forenoon on the first Sunday of November and shall be called
# Yukon Daylight Saving Time.
#
# 2. Order-in-Council 1987/56 is revoked.
#
# 3. This order comes into force January 1, 2007.
#
# * Interpretation Act, RSY 2002, c 125
# https://www.canlii.org/en/yk/laws/stat/rsy-2002-c-125/latest/rsy-2002-c-125.html
# From Rives McDow (1999-09-04):
# Nunavut ... moved ... to incorporate the whole territory into one time zone.
# Nunavut moves to single time zone Oct. 31
# http://www.nunatsiaq.com/nunavut/nvt90903_13.html
#
# From Antoine Leca (1999-09-06):
# We then need to create a new timezone for the Kitikmeot region of Nunavut
# to differentiate it from the Yellowknife region.
# From Paul Eggert (1999-09-20):
# Basic Facts: The New Territory
# http://www.nunavut.com/basicfacts/english/basicfacts_1territory.html
# (1999) reports that Pangnirtung operates on eastern time,
# and that Coral Harbour does not observe DST. We don't know when
# Pangnirtung switched to eastern time; we'll guess 1995.
# From Rives McDow (1999-11-08):
# On October 31, when the rest of Nunavut went to Central time,
# Pangnirtung wobbled. Here is the result of their wobble:
#
# The following businesses and organizations in Pangnirtung use Central Time:
#
# First Air, Power Corp, Nunavut Construction, Health Center, RCMP,
# Eastern Arctic National Parks, A & D Specialist
#
# The following businesses and organizations in Pangnirtung use Eastern Time:
#
# Hamlet office, All other businesses, Both schools, Airport operator
#
# This has made for an interesting situation there, which warranted the news.
# No one there that I spoke with seems concerned, or has plans to
# change the local methods of keeping time, as it evidently does not
# really interfere with any activities or make things difficult locally.
# They plan to celebrate New Year's turn-over twice, one hour apart,
# so it appears that the situation will last at least that long.
# The Nunavut Intergovernmental Affairs hopes that they will "come to
# their senses", but the locals evidently don't see any problem with
# the current state of affairs.
# From Michaela Rodrigue, writing in the
# Nunatsiaq News (1999-11-19):
# http://www.nunatsiaqonline.ca/archives/nunavut991130/nvt91119_17.html
# Clyde River, Pangnirtung and Sanikiluaq now operate with two time zones,
# central - or Nunavut time - for government offices, and eastern time
# for municipal offices and schools.... Igloolik [was similar but then]
# made the switch to central time on Saturday, Nov. 6.
# From Paul Eggert (2000-10-02):
# Matthews and Vincent (1998) say the following, but we lack histories
# for these potential new Zones.
#
# The Canadian Forces station at Alert uses Eastern Time while the
# handful of residents at the Eureka weather station [in the Central
# zone] skip daylight savings. Baffin Island, which is crossed by the
# Central, Eastern and Atlantic Time zones only uses Eastern Time.
# Gjoa Haven, Taloyoak and Pelly Bay all use Mountain instead of
# Central Time and Southampton Island [in the Central zone] is not
# required to use daylight savings.
# From <http://www.nunatsiaqonline.ca/archives/nunavut001130/nvt21110_02.html>
# Nunavut now has two time zones (2000-11-10):
# The Nunavut government would allow its employees in Kugluktuk and
# Cambridge Bay to operate on central time year-round, putting them
# one hour behind the rest of Nunavut for six months during the winter.
# At the end of October the two communities had rebelled against
# Nunavut's unified time zone, refusing to shift to eastern time with
# the rest of the territory for the winter. Cambridge Bay remained on
# central time, while Kugluktuk, even farther west, reverted to
# mountain time, which they had used before the advent of Nunavut's
# unified time zone in 1999.
#
# From Rives McDow (2001-01-20), quoting the Nunavut government:
# The preceding decision came into effect at midnight, Saturday Nov 4, 2000.
# From Paul Eggert (2000-12-04):
# Let's just keep track of the official times for now.
# From Rives McDow (2001-03-07):
# The premier of Nunavut has issued a ministerial statement advising
# that effective 2001-04-01, the territory of Nunavut will revert
# back to three time zones (mountain, central, and eastern). Of the
# cities in Nunavut, Coral Harbor is the only one that I know of that
# has said it will not observe dst, staying on EST year round. I'm
# checking for more info, and will get back to you if I come up with
# more.
# [Also see <http://www.nunatsiaq.com/nunavut/nvt10309_06.html> (2001-03-09).]
# From Gwillim Law (2005-05-21):
# According to ...
# http://www.canadiangeographic.ca/Magazine/SO98/geomap.asp
# (from a 1998 Canadian Geographic article), the de facto and de jure time
# for Southampton Island (at the north end of Hudson Bay) is UTC-5 all year
# round. Using Google, it's easy to find other websites that confirm this.
# I wasn't able to find how far back this time regimen goes, but since it
# predates the creation of Nunavut, it probably goes back many years....
# The Inuktitut name of Coral Harbour is Sallit, but it's rarely used.
#
# From Paul Eggert (2014-10-17):
# For lack of better information, assume that Southampton Island observed
# daylight saving only during wartime. Gwillim Law's email also
# mentioned maps now maintained by National Research Council Canada;
# see above for an up-to-date link.
# From Chris Walton (2007-03-01):
# ... the community of Resolute (located on Cornwallis Island in
# Nunavut) moved from Central Time to Eastern Time last November.
# Basically the community did not change its clocks at the end of
# daylight saving....
# http://www.nnsl.com/frames/newspapers/2006-11/nov13_06none.html
# From Chris Walton (2011-03-21):
# Back in 2007 I initiated the creation of a new "zone file" for Resolute
# Bay. Resolute Bay is a small community located about 900km north of
# the Arctic Circle. The zone file was required because Resolute Bay had
# decided to use UTC-5 instead of UTC-6 for the winter of 2006-2007.
#
# According to new information which I received last week, Resolute Bay
# went back to using UTC-6 in the winter of 2007-2008...
#
# On March 11/2007 most of Canada went onto daylight saving. On March
# 14/2007 I phoned the Resolute Bay hamlet office to do a "time check." I
# talked to somebody that was both knowledgeable and helpful. I was able
# to confirm that Resolute Bay was still operating on UTC-5. It was
# explained to me that Resolute Bay had been on the Eastern Time zone
# (EST) in the winter, and was now back on the Central Time zone (CDT).
# i.e. the time zone had changed twice in the last year but the clocks
# had not moved. The residents had to know which time zone they were in
# so they could follow the correct TV schedule...
#
# On Nov 02/2008 most of Canada went onto standard time. On Nov 03/2008 I
# phoned the Resolute Bay hamlet office...[D]ue to the challenging nature
# of the phone call, I decided to seek out an alternate source of
# information. I found an e-mail address for somebody by the name of
# Stephanie Adams whose job was listed as "Inns North Support Officer for
# Arctic Co-operatives." I was under the impression that Stephanie lived
# and worked in Resolute Bay...
#
# On March 14/2011 I phoned the hamlet office again. I was told that
# Resolute Bay had been using Central Standard Time over the winter of
# 2010-2011 and that the clocks had therefore been moved one hour ahead
# on March 13/2011. The person I talked to was aware that Resolute Bay
# had previously experimented with Eastern Standard Time but he could not
# tell me when the practice had stopped.
#
# On March 17/2011 I searched the Web to find an e-mail address of
# somebody that might be able to tell me exactly when Resolute Bay went
# off Eastern Standard Time. I stumbled on the name "Aziz Kheraj." Aziz
# used to be the mayor of Resolute Bay and he apparently owns half the
# businesses including "South Camp Inn." This website has some info on
# Aziz:
# http://www.uphere.ca/node/493
#
# I sent Aziz an e-mail asking when Resolute Bay had stopped using
# Eastern Standard Time.
#
# Aziz responded quickly with this: "hi, The time was not changed for the
# 1 year only, the following year, the community went back to the old way
# of "spring ahead-fall behind" currently we are zulu plus 5 hrs and in
# the winter Zulu plus 6 hrs"
#
# This of course conflicted with everything I had ascertained in November 2008.
#
# I sent Aziz a copy of my 2008 e-mail exchange with Stephanie. Aziz
# responded with this: "Hi, Stephanie lives in Winnipeg. I live here, You
# may want to check with the weather office in Resolute Bay or do a
# search on the weather through Env. Canada. web site"
#
# If I had realized the Stephanie did not live in Resolute Bay I would
# never have contacted her. I now believe that all the information I
# obtained in November 2008 should be ignored...
# I apologize for reporting incorrect information in 2008.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule NT_YK 1918 only - Apr 14 2:00 1:00 D
Rule NT_YK 1918 only - Oct 27 2:00 0 S
Rule NT_YK 1919 only - May 25 2:00 1:00 D
Rule NT_YK 1919 only - Nov 1 0:00 0 S
Rule NT_YK 1942 only - Feb 9 2:00 1:00 W # War
Rule NT_YK 1945 only - Aug 14 23:00u 1:00 P # Peace
Rule NT_YK 1945 only - Sep 30 2:00 0 S
Rule NT_YK 1965 only - Apr lastSun 0:00 2:00 DD
Rule NT_YK 1965 only - Oct lastSun 2:00 0 S
Rule NT_YK 1980 1986 - Apr lastSun 2:00 1:00 D
Rule NT_YK 1980 2006 - Oct lastSun 2:00 0 S
Rule NT_YK 1987 2006 - Apr Sun>=1 2:00 1:00 D
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
# aka Panniqtuuq
Zone America/Pangnirtung 0 - -00 1921 # trading post est.
-4:00 NT_YK A%sT 1995 Apr Sun>=1 2:00
-5:00 Canada E%sT 1999 Oct 31 2:00
-6:00 Canada C%sT 2000 Oct 29 2:00
-5:00 Canada E%sT
# formerly Frobisher Bay
Zone America/Iqaluit 0 - -00 1942 Aug # Frobisher Bay est.
-5:00 NT_YK E%sT 1999 Oct 31 2:00
-6:00 Canada C%sT 2000 Oct 29 2:00
-5:00 Canada E%sT
# aka Qausuittuq
Zone America/Resolute 0 - -00 1947 Aug 31 # Resolute founded
-6:00 NT_YK C%sT 2000 Oct 29 2:00
-5:00 - EST 2001 Apr 1 3:00
-6:00 Canada C%sT 2006 Oct 29 2:00
-5:00 - EST 2007 Mar 11 3:00
-6:00 Canada C%sT
# aka Kangiqiniq
Zone America/Rankin_Inlet 0 - -00 1957 # Rankin Inlet founded
-6:00 NT_YK C%sT 2000 Oct 29 2:00
-5:00 - EST 2001 Apr 1 3:00
-6:00 Canada C%sT
# aka Iqaluktuuttiaq
Zone America/Cambridge_Bay 0 - -00 1920 # trading post est.?
-7:00 NT_YK M%sT 1999 Oct 31 2:00
-6:00 Canada C%sT 2000 Oct 29 2:00
-5:00 - EST 2000 Nov 5 0:00
-6:00 - CST 2001 Apr 1 3:00
-7:00 Canada M%sT
Zone America/Yellowknife 0 - -00 1935 # Yellowknife founded?
-7:00 NT_YK M%sT 1980
-7:00 Canada M%sT
Zone America/Inuvik 0 - -00 1953 # Inuvik founded
-8:00 NT_YK P%sT 1979 Apr lastSun 2:00
-7:00 NT_YK M%sT 1980
-7:00 Canada M%sT
Zone America/Whitehorse -9:00:12 - LMT 1900 Aug 20
-9:00 NT_YK Y%sT 1967 May 28 0:00
-8:00 NT_YK P%sT 1980
-8:00 Canada P%sT
Zone America/Dawson -9:17:40 - LMT 1900 Aug 20
-9:00 NT_YK Y%sT 1973 Oct 28 0:00
-8:00 NT_YK P%sT 1980
-8:00 Canada P%sT
###############################################################################
# Mexico
# From Paul Eggert (2014-12-07):
# The Investigation and Analysis Service of the
# Mexican Library of Congress (MLoC) has published a
# history of Mexican local time (in Spanish)
# http://www.diputados.gob.mx/bibliot/publica/inveyana/polisoc/horver/index.htm
#
# Here are the discrepancies between Shanks & Pottenger (S&P) and the MLoC.
# (In all cases we go with the MLoC.)
# S&P report that Baja was at -8:00 in 1922/1923.
# S&P say the 1930 transition in Baja was 1930-11-16.
# S&P report no DST during summer 1931.
# S&P report a transition at 1932-03-30 23:00, not 1932-04-01.
# From Gwillim Law (2001-02-20):
# There are some other discrepancies between the Decrees page and the
# tz database. I think they can best be explained by supposing that
# the researchers who prepared the Decrees page failed to find some of
# the relevant documents.
# From Alan Perry (1996-02-15):
# A guy from our Mexico subsidiary finally found the Presidential Decree
# outlining the timezone changes in Mexico.
#
# ------------- Begin Forwarded Message -------------
#
# I finally got my hands on the Official Presidential Decree that sets up the
# rules for the DST changes. The rules are:
#
# 1. The country is divided in 3 timezones:
# - Baja California Norte (the Mexico/BajaNorte TZ)
# - Baja California Sur, Nayarit, Sinaloa and Sonora (the Mexico/BajaSur TZ)
# - The rest of the country (the Mexico/General TZ)
#
# 2. From the first Sunday in April at 2:00 AM to the last Sunday in October
# at 2:00 AM, the times in each zone are as follows:
# BajaNorte: GMT+7
# BajaSur: GMT+6
# General: GMT+5
#
# 3. The rest of the year, the times are as follows:
# BajaNorte: GMT+8
# BajaSur: GMT+7
# General: GMT+6
#
# The Decree was published in Mexico's Official Newspaper on January 4th.
#
# -------------- End Forwarded Message --------------
# From Paul Eggert (1996-06-12):
# For an English translation of the decree, see
# "Diario Oficial: Time Zone Changeover" (1996-01-04).
# http://mexico-travel.com/extra/timezone_eng.html
# From Rives McDow (1998-10-08):
# The State of Quintana Roo has reverted back to central STD and DST times
# (i.e. UTC -0600 and -0500 as of 1998-08-02).
# From Rives McDow (2000-01-10):
# Effective April 4, 1999 at 2:00 AM local time, Sonora changed to the time
# zone 5 hours from the International Date Line, and will not observe daylight
# savings time so as to stay on the same time zone as the southern part of
# Arizona year round.
# From Jesper Nørgaard, translating
# <http://www.reforma.com/nacional/articulo/064327/> (2001-01-17):
# In Oaxaca, the 55.000 teachers from the Section 22 of the National
# Syndicate of Education Workers, refuse to apply daylight saving each
# year, so that the more than 10,000 schools work at normal hour the
# whole year.
# From Gwillim Law (2001-01-19):
# <http://www.reforma.com/negocios_y_dinero/articulo/064481/> ... says
# (translated):...
# January 17, 2000 - The Energy Secretary, Ernesto Martens, announced
# that Summer Time will be reduced from seven to five months, starting
# this year....
# http://www.publico.com.mx/scripts/texto3.asp?action=pagina&pag=21&pos=p&secc=naci&date=01/17/2001
# [translated], says "summer time will ... take effect on the first Sunday
# in May, and end on the last Sunday of September.
# From Arthur David Olson (2001-01-25):
# The 2001-01-24 traditional Washington Post contained the page one
# story "Timely Issue Divides Mexicans."...
# http://www.washingtonpost.com/wp-dyn/articles/A37383-2001Jan23.html
# ... Mexico City Mayor López Obrador "...is threatening to keep
# Mexico City and its 20 million residents on a different time than
# the rest of the country..." In particular, López Obrador would abolish
# observation of Daylight Saving Time.
# Official statute published by the Energy Department
# http://www.conae.gob.mx/ahorro/decretohorver2001.html#decre
# (2001-02-01) shows Baja and Chihauhua as still using US DST rules,
# and Sonora with no DST. This was reported by Jesper Nørgaard (2001-02-03).
# From Paul Eggert (2001-03-03):
#
# http://www.latimes.com/news/nation/20010303/t000018766.html
# James F. Smith writes in today's LA Times
# * Sonora will continue to observe standard time.
# * Last week Mexico City's mayor Andrés Manuel López Obrador decreed that
# the Federal District will not adopt DST.
# * 4 of 16 district leaders announced they'll ignore the decree.
# * The decree does not affect federal-controlled facilities including
# the airport, banks, hospitals, and schools.
#
# For now we'll assume that the Federal District will bow to federal rules.
# From Jesper Nørgaard (2001-04-01):
# I found some references to the Mexican application of daylight
# saving, which modifies what I had already sent you, stating earlier
# that a number of northern Mexican states would go on daylight
# saving. The modification reverts this to only cover Baja California
# (Norte), while all other states (except Sonora, who has no daylight
# saving all year) will follow the original decree of president
# Vicente Fox, starting daylight saving May 6, 2001 and ending
# September 30, 2001.
# References: "Diario de Monterrey" <http://www.diariodemonterrey.com/index.asp>
# Palabra <http://palabra.infosel.com/010331/primera/ppri3101.pdf> (2001-03-31)
# From Reuters (2001-09-04):
# Mexico's Supreme Court on Tuesday declared that daylight savings was
# unconstitutional in Mexico City, creating the possibility the
# capital will be in a different time zone from the rest of the nation
# next year.... The Supreme Court's ruling takes effect at 2:00
# a.m. (0800 GMT) on Sept. 30, when Mexico is scheduled to revert to
# standard time. "This is so residents of the Federal District are not
# subject to unexpected time changes," a statement from the court said.
# From Jesper Nørgaard Welen (2002-03-12):
# ... consulting my local grocery store(!) and my coworkers, they all insisted
# that a new decision had been made to reinstate US style DST in Mexico....
# http://www.conae.gob.mx/ahorro/horaver2001_m1_2002.html (2002-02-20)
# confirms this. Sonora as usual is the only state where DST is not applied.
# From Steffen Thorsen (2009-12-28):
#
# Steffen Thorsen wrote:
# > Mexico's House of Representatives has approved a proposal for northern
# > Mexico's border cities to share the same daylight saving schedule as
# > the United States.
# Now this has passed both the Congress and the Senate, so starting from
# 2010, some border regions will be the same:
# http://www.signonsandiego.com/news/2009/dec/28/clocks-will-match-both-sides-border/
# http://www.elmananarey.com/diario/noticia/nacional/noticias/empatan_horario_de_frontera_con_eu/621939
# (Spanish)
#
# Could not find the new law text, but the proposed law text changes are here:
# http://gaceta.diputados.gob.mx/Gaceta/61/2009/dic/20091210-V.pdf
# (Gaceta Parlamentaria)
#
# There is also a list of the votes here:
# http://gaceta.diputados.gob.mx/Gaceta/61/2009/dic/V2-101209.html
#
# Our page:
# https://www.timeanddate.com/news/time/north-mexico-dst-change.html
# From Arthur David Olson (2010-01-20):
# The page
# http://dof.gob.mx/nota_detalle.php?codigo=5127480&fecha=06/01/2010
# includes this text:
# En los municipios fronterizos de Tijuana y Mexicali en Baja California;
# Juárez y Ojinaga en Chihuahua; Acuña y Piedras Negras en Coahuila;
# Anáhuac en Nuevo León; y Nuevo Laredo, Reynosa y Matamoros en
# Tamaulipas, la aplicación de este horario estacional surtirá efecto
# desde las dos horas del segundo domingo de marzo y concluirá a las dos
# horas del primer domingo de noviembre.
# En los municipios fronterizos que se encuentren ubicados en la franja
# fronteriza norte en el territorio comprendido entre la línea
# internacional y la línea paralela ubicada a una distancia de veinte
# kilómetros, así como la Ciudad de Ensenada, Baja California, hacia el
# interior del país, la aplicación de este horario estacional surtirá
# efecto desde las dos horas del segundo domingo de marzo y concluirá a
# las dos horas del primer domingo de noviembre.
# From Steffen Thorsen (2014-12-08), translated by Gwillim Law:
# The Mexican state of Quintana Roo will likely change to EST in 2015.
#
# http://www.unioncancun.mx/articulo/2014/12/04/medio-ambiente/congreso-aprueba-una-hora-mas-de-sol-en-qroo
# "With this change, the time conflict that has existed between the municipios
# of Quintana Roo and the municipio of Felipe Carrillo Puerto may come to an
# end. The latter declared itself in rebellion 15 years ago when a time change
# was initiated in Mexico, and since then it has refused to change its time
# zone along with the rest of the country."
#
# From Steffen Thorsen (2015-01-14), translated by Gwillim Law:
# http://sipse.com/novedades/confirman-aplicacion-de-nueva-zona-horaria-para-quintana-roo-132331.html
# "...the new time zone will come into effect at two o'clock on the first Sunday
# of February, when we will have to advance the clock one hour from its current
# time..."
# Also, the new zone will not use DST.
#
# From Carlos Raúl Perasso (2015-02-02):
# The decree that modifies the Mexican Hour System Law has finally
# been published at the Diario Oficial de la Federación
# http://www.dof.gob.mx/nota_detalle.php?codigo=5380123&fecha=31/01/2015
# It establishes 5 zones for Mexico:
# 1- Zona Centro (Central Zone): Corresponds to longitude 90 W,
# includes most of Mexico, excluding what's mentioned below.
# 2- Zona Pacífico (Pacific Zone): Longitude 105 W, includes the
# states of Baja California Sur; Chihuahua; Nayarit (excluding Bahía
# de Banderas which lies in Central Zone); Sinaloa and Sonora.
# 3- Zona Noroeste (Northwest Zone): Longitude 120 W, includes the
# state of Baja California.
# 4- Zona Sureste (Southeast Zone): Longitude 75 W, includes the state
# of Quintana Roo.
# 5- The islands, reefs and keys shall take their timezone from the
# longitude they are located at.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Mexico 1939 only - Feb 5 0:00 1:00 D
Rule Mexico 1939 only - Jun 25 0:00 0 S
Rule Mexico 1940 only - Dec 9 0:00 1:00 D
Rule Mexico 1941 only - Apr 1 0:00 0 S
Rule Mexico 1943 only - Dec 16 0:00 1:00 W # War
Rule Mexico 1944 only - May 1 0:00 0 S
Rule Mexico 1950 only - Feb 12 0:00 1:00 D
Rule Mexico 1950 only - Jul 30 0:00 0 S
Rule Mexico 1996 2000 - Apr Sun>=1 2:00 1:00 D
Rule Mexico 1996 2000 - Oct lastSun 2:00 0 S
Rule Mexico 2001 only - May Sun>=1 2:00 1:00 D
Rule Mexico 2001 only - Sep lastSun 2:00 0 S
Rule Mexico 2002 max - Apr Sun>=1 2:00 1:00 D
Rule Mexico 2002 max - Oct lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
# Quintana Roo; represented by Cancún
Zone America/Cancun -5:47:04 - LMT 1922 Jan 1 0:12:56
-6:00 - CST 1981 Dec 23
-5:00 Mexico E%sT 1998 Aug 2 2:00
-6:00 Mexico C%sT 2015 Feb 1 2:00
-5:00 - EST
# Campeche, Yucatán; represented by Mérida
Zone America/Merida -5:58:28 - LMT 1922 Jan 1 0:01:32
-6:00 - CST 1981 Dec 23
-5:00 - EST 1982 Dec 2
-6:00 Mexico C%sT
# Coahuila, Nuevo León, Tamaulipas (near US border)
# This includes the following municipalities:
# in Coahuila: Ocampo, Acuña, Zaragoza, Jiménez, Piedras Negras, Nava,
# Guerrero, Hidalgo.
# in Nuevo León: Anáhuac, Los Aldama.
# in Tamaulipas: Nuevo Laredo, Guerrero, Mier, Miguel Alemán, Camargo,
# Gustavo Díaz Ordaz, Reynosa, Río Bravo, Valle Hermoso, Matamoros.
# See: Inicia mañana Horario de Verano en zona fronteriza, El Universal,
# 2016-03-12
# http://www.eluniversal.com.mx/articulo/estados/2016/03/12/inicia-manana-horario-de-verano-en-zona-fronteriza
Zone America/Matamoros -6:40:00 - LMT 1921 Dec 31 23:20:00
-6:00 - CST 1988
-6:00 US C%sT 1989
-6:00 Mexico C%sT 2010
-6:00 US C%sT
# Durango; Coahuila, Nuevo León, Tamaulipas (away from US border)
Zone America/Monterrey -6:41:16 - LMT 1921 Dec 31 23:18:44
-6:00 - CST 1988
-6:00 US C%sT 1989
-6:00 Mexico C%sT
# Central Mexico
Zone America/Mexico_City -6:36:36 - LMT 1922 Jan 1 0:23:24
-7:00 - MST 1927 Jun 10 23:00
-6:00 - CST 1930 Nov 15
-7:00 - MST 1931 May 1 23:00
-6:00 - CST 1931 Oct
-7:00 - MST 1932 Apr 1
-6:00 Mexico C%sT 2001 Sep 30 2:00
-6:00 - CST 2002 Feb 20
-6:00 Mexico C%sT
# Chihuahua (near US border)
# This includes the municipalities of Janos, Ascensión, Juárez, Guadalupe,
# Práxedis G Guerrero, Coyame del Sotol, Ojinaga, and Manuel Benavides.
# (See the 2016-03-12 El Universal source mentioned above.)
Zone America/Ojinaga -6:57:40 - LMT 1922 Jan 1 0:02:20
-7:00 - MST 1927 Jun 10 23:00
-6:00 - CST 1930 Nov 15
-7:00 - MST 1931 May 1 23:00
-6:00 - CST 1931 Oct
-7:00 - MST 1932 Apr 1
-6:00 - CST 1996
-6:00 Mexico C%sT 1998
-6:00 - CST 1998 Apr Sun>=1 3:00
-7:00 Mexico M%sT 2010
-7:00 US M%sT
# Chihuahua (away from US border)
Zone America/Chihuahua -7:04:20 - LMT 1921 Dec 31 23:55:40
-7:00 - MST 1927 Jun 10 23:00
-6:00 - CST 1930 Nov 15
-7:00 - MST 1931 May 1 23:00
-6:00 - CST 1931 Oct
-7:00 - MST 1932 Apr 1
-6:00 - CST 1996
-6:00 Mexico C%sT 1998
-6:00 - CST 1998 Apr Sun>=1 3:00
-7:00 Mexico M%sT
# Sonora
Zone America/Hermosillo -7:23:52 - LMT 1921 Dec 31 23:36:08
-7:00 - MST 1927 Jun 10 23:00
-6:00 - CST 1930 Nov 15
-7:00 - MST 1931 May 1 23:00
-6:00 - CST 1931 Oct
-7:00 - MST 1932 Apr 1
-6:00 - CST 1942 Apr 24
-7:00 - MST 1949 Jan