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# @(#)northamerica 7.30
# also includes Central America and the Caribbean
# This data is by no means authoritative; if you think you know better,
# go ahead and edit the file (and please send any changes to
# tz@elsie.nci.nih.gov for general use in the future).
# From Paul Eggert <eggert@twinsun.com> (1994-08-17):
# A reliable and entertaining source about time zones is
# Derek Howse, Greenwich time and the discovery of the longitude,
# Oxford University Press (1980).
###############################################################################
# United States
# From Paul Eggert <eggert@twinsun.com> (1995-12-19):
# 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 the US and Puerto Rico entries below.
# From Paul Eggert (1996-06-12):
# Daylight Saving Time was first suggested as a joke by Benjamin Franklin
# in his whimsical essay ``Turkey vs Eagle, McCauley is my Beagle'' (1784).
# 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 (1947), XIX, Sunday
# 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.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule US 1918 1919 - Mar lastSun 2:00 1:00 W # War
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 - Sep 30 2:00 0 S
Rule US 1967 max - 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 max - Apr Sun>=1 2:00 1:00 D
# From Bob Devine (1988-01-28):
# ...Alaska (and Hawaii) had the timezone names changed in 1967.
# old new
# Pacific Standard Time(PST) -same-
# Yukon Standard Time(YST) -same-
# Central Alaska S.T. (CAT) Alaska-Hawaii St[an]dard Time (AHST)
# Nome Standard Time (NT) Bering Standard Time (BST)
#
# ...Alaska's timezone lines were redrawn in 1983 to give only 2 tz.
# The YST zone now covers nearly all of the state, AHST just part
# of the Aleutian islands. No DST.
# From Paul Eggert (1995-12-19):
# The tables below use `NST', not `NT', for Nome Standard Time.
# I invented `CAWT' for Central Alaska War Time.
# 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 (1995-12-19):
# Shanks uses 1983-10-30, not 1983-11-30, for the 1983 transitions.
# Go with Shanks.
# US Eastern time, represented by New York
# 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 12:00
-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
# 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 12:00
-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
# US Mountain time, represented by Denver
# 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
-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
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER
Rule CA 1948 only - Mar 14 2:00 1:00 D
Rule CA 1949 only - Jan 1 2:00 0 S
Rule CA 1950 1966 - Apr lastSun 2:00 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 12:00
-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 -9:00 per USNO.
#
# From Paul Eggert (1995-12-19):
# 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.
# This was on 1867-10-18. We omit this transition, since we can't represent
# changes from Julian to Gregorian.
#
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Juneau -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 1983 Oct 30 2:00
-9:00 US AK%sT
Zone America/Yakutat -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 Oct 30 2:00
-9:00 US AK%sT
Zone America/Anchorage -9:59:36 - LMT 1900 Aug 20 12:00
-10:00 - CAT 1942
-10:00 US CAT/CAWT 1946
-10:00 - CAT 1967 Apr
-10:00 - AHST 1969
-10:00 US AH%sT 1983 Oct 30 2:00
-9:00 US AK%sT
Zone America/Nome -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 AK%sT
Zone America/Adak -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 HA%sT
# 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.
# These switches don't quite make our 1970 cutoff.
# Hawaii
#
# From Arthur David Olson:
# And then there's Hawaii.
# DST was observed for one day in 1933;
# standard time was changed by half an hour in 1947;
# it's always standard as of 1986.
#
# From Paul Eggert:
# Shanks says the 1933 experiment lasted for three weeks. Go with Shanks.
#
Zone Pacific/Honolulu -10:31:26 - LMT 1900 Jan 1 12:00
-10:30 - HST 1933 Apr 30 2:00
-10:30 1:00 HDT 1933 May 21 2:00
-10:30 US H%sT 1947 Jun 8 2:00
-10:00 - HST
Zone Pacific/Midway -11:49:28 - LMT 1901
-11:00 - NST 1967 Apr # N=Nome
-11:00 - BST 1983 Nov 30 # B=Bering
-11:00 - SST # S=Samoa
# Now we turn to US areas that have diverged from the consensus since 1970.
# Arizona mostly uses MST.
Zone America/Phoenix -7:28:18 - LMT 1883 Nov 18 12:00
-7:00 US M%sT 1944 Jan 1 00:01
-7:00 - MST 1944 Mar 17 00:01
-7:00 US M%sT 1944 Oct 1 00:01
-7:00 - MST 1967
-7:00 US M%sT 1968
-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 12/28/87 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.)
Link America/Denver America/Shiprock
# Southern Idaho and eastern Oregon switched four weeks late in 1974.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Boise -7:44:49 - LMT 1883 Nov 18 12:00
-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
#
# From Paul Eggert (1995-12-19):
# Indiana generally observes either EST all year, or CST/CDT,
# but areas near Cincinnati and Louisville use those cities' timekeeping
# and in 1969 and 1970 the whole state observed daylight time;
# and there are other exceptions as noted below.
# Shanks partitions Indiana into 345 regions, each with its own time history,
# and writes ``Even newspaper reports present contradictory information.''
# Fortunately, most of the complexity occurred before our cutoff date of 1970.
#
# Since 1970, EST-only Indiana has been like America/Indianapolis,
# with exceptions noted below for Crawford, Starke, and Switzerland counties.
# The parts of Indiana not listed below have been like America/Chicago,
# America/Louisville, or America/New_York.
#
# 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'.
#
# Most of EST-only Indiana last observed DST in 1970.
# 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/Indianapolis -5:44:38 - LMT 1883 Nov 18 12:00
-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
Link America/Indianapolis America/Indiana/Indianapolis
#
# Part of Crawford County, Indiana, last observed DST in 1975,
# and left its clocks alone in 1974.
# 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 12:00
-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
#
# Starke County, Indiana
# 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 12:00
-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
#
# Switzerland County, Indiana, last observed DST in 1972.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Indiana/Vevay -5:40:16 - LMT 1883 Nov 18 12:00
-6:00 US C%sT 1954 Apr 25 2:00
-5:00 - EST 1969
-5:00 US E%sT 1973
-5:00 - EST
# Part of Kentucky left its clocks alone in 1974.
# 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/Louisville -5:43:02 - LMT 1883 Nov 18 12:00
-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
# Michigan
#
# From Bob Devine (1988-01-28):
# Michigan didn't observe DST from 1968 to 1973.
#
# From Paul Eggert (1995-12-19):
# Shanks writes that Michigan started using standard time on 1885 Sep 18,
# but Howse (p 126) writes 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.
#
# 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
Rule Detroit 1967 only - Jun 14 2:00 1:00 D
Rule Detroit 1967 only - Oct 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
#
# The Michigan border with Wisconsin 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
# uninhabited
# Old names, for S5 users
# Link LINK-FROM LINK-TO
Link America/New_York EST5EDT
Link America/Chicago CST6CDT
Link America/Denver MST7MDT
Link America/Los_Angeles PST8PDT
Link America/Indianapolis EST
Link America/Phoenix MST
Link Pacific/Honolulu HST
################################################################################
# From Paul Eggert <eggert@twinsun.com> (1996-11-22):
# A good source for time zone historical data outside the US is
# Thomas G. Shanks, The International Atlas (3rd edition),
# San Diego: ACS Publications, Inc. (1991).
#
# Gwillim Law <LAW@encmail.encompass.com> writes that a good source
# for recent time zone data is 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, Shanks is the source for entries through 1990,
# and IATA SSIM is the source for entries after 1990.
#
# Another source occasionally used is Edward W. Whitman, World Time Differences,
# Whitman Publishing Co, 2 Niagara Av, Ealing, London (undated), which
# I found in the UCLA library.
#
# See the `europe' file for Greenland.
#
# See the `africa' file for time zone naming and abbreviation conventions.
# Canada
# From Alain LaBont<e'> <ALB@immedia.ca> (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 savings 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 Avanc<e'>e 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 <eggert@twinsun.com> (1994-11-22):
# Alas, this sort of thing must be handled by localization software.
# The data for Canada are all from Shanks (1991).
# 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 31 2:00 0 S
Rule Canada 1942 only - Feb 9 2:00 1:00 D
Rule Canada 1945 only - Sep 30 2:00 0 S
Rule Canada 1974 1986 - Apr lastSun 2:00 1:00 D
Rule Canada 1974 max - Oct lastSun 2:00 0 S
Rule Canada 1987 max - Apr Sun>=1 2:00 1:00 D
# Newfoundland (except Labrador)
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule StJohns 1917 1918 - Apr Sun>=8 2:00 1:00 D
Rule StJohns 1917 only - Sep 17 2:00 0 S
Rule StJohns 1918 only - Oct 31 2:00 0 S
# Whitman gives 1919 Apr 5 and 1920 Apr 5; go with Shanks.
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.
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 Shanks gives May Mon>=9 and Oct Mon>=2; go with Whitman.
Rule StJohns 1936 1941 - May Sun>=8 0:00 1:00 D
Rule StJohns 1936 1941 - Oct Sun>=1 0:00 0 S
# Shanks gives 1942 May 11 - 1945 Sep 30; go with Whitman.
Rule StJohns 1942 only - Mar 1 0:00 1:00 D
Rule StJohns 1942 only - Dec 31 0:00 0 S
Rule StJohns 1943 only - May 30 0:00 1:00 D
Rule StJohns 1943 only - Sep 5 0:00 0 S
Rule StJohns 1944 only - Jul 10 0:00 1:00 D
Rule StJohns 1944 only - Sep 2 0:00 0 S
Rule StJohns 1945 only - Jan 1 0:00 1:00 D
Rule StJohns 1945 only - Oct 7 2:00 0 S
# 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.
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 max - Oct lastSun 2:00 0 S
Rule StJohns 1987 only - Apr Sun>=1 2:00 1:00 D
Rule StJohns 1988 only - Apr Sun>=1 2:00 2:00 DD
Rule StJohns 1989 max - Apr Sun>=1 2:00 1:00 D
# 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 1935 Mar 30
-3:30 StJohns N%sT
# 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 StJohns NST 1919
-3:30:52 - NST 1935 Mar 30
-3:30 - NST 1936
-3:30 StJohns N%sT 1966 Mar 15 2:00
-4:00 StJohns A%sT
# west Labrador, New Brunswick, Nova Scotia, Prince Edward I
# From Paul Eggert (1996-06-12):
# Shanks writes that since 1970 most of this region has been like Halifax.
# Many locales did not observe peacetime DST until 1972;
# Glace Bay, NS is the largest that we know of.
# Shanks also writes 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 1918 only - Apr 14 2:00 1:00 D
Rule Halifax 1918 only - Oct 31 2:00 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 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 1942 only - Feb 9 2:00 1:00 D
Rule Halifax 1945 1959 - Sep lastSun 2:00 0 S
Rule Halifax 1946 1959 - Apr lastSun 2:00 1:00 D
Rule Halifax 1962 1986 - Apr lastSun 2:00 1:00 D
Rule Halifax 1962 max - Oct lastSun 2:00 0 S
Rule Halifax 1987 max - Apr Sun>=1 2:00 1:00 D
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Halifax -4:14:24 - LMT 1902 Jun 15
-4:00 Halifax 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
# Ontario, Quebec
# From Paul Eggert (1996-06-12):
# Shanks writes that since 1970 most of this region has been like Montreal.
# 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.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Mont 1917 only - Mar 25 2:00 1:00 D
Rule Mont 1917 only - Apr 24 0:00 0 S
Rule Mont 1918 only - Apr 14 2:00 1:00 D
Rule Mont 1918 only - Oct 31 2:00 0 S
Rule Mont 1919 only - Mar 31 2:30 1:00 D
Rule Mont 1919 only - Oct 25 2:30 0 S
Rule Mont 1920 only - May 2 2:30 1:00 D
Rule Mont 1920 only - Oct 3 2:30 0 S
Rule Mont 1921 only - May 1 2:00 1:00 D
Rule Mont 1921 only - Oct 2 2:30 0 S
Rule Mont 1922 only - Apr 30 2:00 1:00 D
Rule Mont 1922 only - Oct 1 2:30 0 S
Rule Mont 1924 only - May 17 2:00 1:00 D
Rule Mont 1924 1926 - Sep lastSun 2:30 0 S
Rule Mont 1925 1926 - May Sun>=1 2:00 1:00 D
Rule Mont 1927 only - May 1 0:00 1:00 D
Rule Mont 1927 1932 - Sep Sun>=25 0:00 0 S
Rule Mont 1928 1931 - Apr Sun>=25 0:00 1:00 D
Rule Mont 1932 only - May 1 0:00 1:00 D
Rule Mont 1933 1940 - Apr Sun>=24 0:00 1:00 D
Rule Mont 1933 only - Oct 1 0:00 0 S
Rule Mont 1934 1939 - Sep Sun>=24 0:00 0 S
Rule Mont 1945 1948 - Sep lastSun 2:00 0 S
Rule Mont 1946 1986 - Apr lastSun 2:00 1:00 D
Rule Mont 1949 1950 - Oct lastSun 2:00 0 S
Rule Mont 1951 1956 - Sep lastSun 2:00 0 S
Rule Mont 1957 max - Oct lastSun 2:00 0 S
Rule Mont 1987 max - Apr Sun>=1 2:00 1:00 D
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Montreal -4:54:16 - LMT 1884
-5:00 Mont E%sT
Zone America/Thunder_Bay -5:57:00 - LMT 1895
-5:00 Canada E%sT 1970
-5:00 Mont 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
Zone America/Rainy_River -6:17:56 - LMT 1895
-6:00 Canada C%sT
# Manitoba
# 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 31 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 D
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 2:00 1:00 D
Rule Winn 1966 max - Oct lastSun 2:00 0 S
Rule Winn 1987 max - Apr Sun>=1 2:00 1:00 D
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Winnipeg -6:28:36 - LMT 1887 Jul 16
-6:00 Winn C%sT
# Saskatchewan
# From Paul Eggert (1996-06-12):
# Shanks writes that since 1970 most of this region has been like 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.
# From W. Jones <jones@skdad.usask.ca> (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.
# 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 31 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 D
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 1959 - Apr lastSun 2:00 1:00 D
Rule Regina 1947 1958 - Sep lastSun 2:00 0 S
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 31 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 D
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 max - Oct lastSun 2:00 0 S
Rule Edm 1987 max - Apr Sun>=1 2:00 1:00 D
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Edmonton -7:33:52 - LMT 1906 Sep
-7:00 Edm M%sT
# British Columbia
# From Paul Eggert (1996-06-12):
# Shanks writes that since 1970 most of this region has been like Vancouver.
# Dawswon Creek uses MST. Much of east BC is like Edmonton.
# 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 31 2:00 0 S
Rule Vanc 1942 only - Feb 9 2:00 1:00 D
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 max - Oct lastSun 2:00 0 S
Rule Vanc 1987 max - Apr Sun>=1 2:00 1:00 D
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Vancouver -8:12:28 - LMT 1884
-8:00 Vanc 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
# Northwest Territories, Yukon
# From Paul Eggert (1996-10-07):
# Dawson switched to PST in 1973. Inuvik switched to MST in 1979.
# Shanks's table for Watson Lake is corrupted, so we have no data there.
# Mathew Englander <mathew@io.org> (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. This is still valid;
# see Interpretation Act, R.S.C. 1985, c. I-21, s. 35(1).
# * 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.
# Shanks says Yukon's 1973-10-28 switch was at 2:00; go with Englander.
# 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 D
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 max - Oct lastSun 2:00 0 S
Rule NT_YK 1987 max - Apr Sun>=1 2:00 1:00 D
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Pangnirtung -4:22:56 - LMT 1884
-4:00 NT_YK A%sT
Zone America/Iqaluit -4:33:52 - LMT 1884 # Frobisher Bay
-5:00 NT_YK E%sT
Zone America/Rankin_Inlet -6:08:40 - LMT 1884
-6:00 NT_YK C%sT
Zone America/Yellowknife -7:37:24 - LMT 1884
-7:00 NT_YK M%sT
Zone America/Inuvik -8:54:00 - LMT 1884
-8:00 NT_YK P%sT 1979 Apr lastSun 2:00
-7:00 NT_YK M%sT
Zone America/Whitehorse -9:00:12 - LMT 1900 Aug 20
-9:00 NT_YK Y%sT 1966 Jul 1 2:00
-8:00 NT_YK 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
###############################################################################
# Mexico
# From Guy Harris:
# Rules are from the Official Airline Guide, Worldwide Edition, for 1987.
# Rules prior to 1987 are unknown.
# The comments in the OAG say "Only Ensenada, Mexicale, San Felipe and Tijuana
# observe DST." This is presumably Baja California Norte, above 28th parallel,
# as listed there; [there is also] "Baja California Sur and N. Pacific
# Coast (States of Sinaloa and Sonora)."
# From Bob Devine (1988-01-28):
# The Federal District (where Mexico City is) has observed [DST] several
# times but not recently.
#
# I don't where to drawn the line in the North Baja area. 28th latitude
# sounds good -- but it may be higher (how far [d]o radio stations from
# San Diego affect culture?).
#
# The dates of DST probably go back to 1981. The rules are the same as
# US's. This is going to be a headache for US presidential electi[o]n years!
# From Arthur David Olson (1988-02-13)
# Since the 1981 starting date is only "probable," we'll keep the 1987
# starting date below.
# From U. S. Naval Observatory (1989-01-19):
# MEXICO BAJA CAL N 7 H BEHIND UTC BAJA CALIFORNIA SUR AND
# MEXICO BAJA CAL N N. PACIFIC COAST (STATES
# MEXICO BAJA CAL N OF SINALOA AND SONORA)
# MEXICO BAJA CAL N 8 H BEHIND UTC ABOVE 28TH PARALLEL APR 3
# MEXICO BAJA CAL N - OCT 29
# MEXICO BAJA CAL N 7 H BEHIND UTC ABOVE 28TH PARALLEL APR 3
# MEXICO BAJA CAL N - 0CT 29
# MEXICO 6 H BEHIND UTC STATES OF DURANGO,
# MEXICO COAHUILA, NUEVO LEON,
# MEXICO TAMAULIPAS
# MEXICO 5 H BEHIND UTC STATES OF DURANGO,
# MEXICO COAHUILA, NUEVO LEON,
# MEXICO TAMAULIPAS APR 3 - OCT 29
# MEXICO 6 H BEHIND UTC GENERAL MEXICO, STATES OF
# MEXICO CAMPECHE, QUINTANA ROO AND
# MEXICO YUCATAN
# From Arthur David Olson (1989-01-21):
# April 3 fell on a Sunday in 1988; October 29 fell on a Sunday in 1989. Ahem.
# USNO claims there should be four Mexican zones rather than three:
# a zone that's GMT-8 with DST; a zone that's always GMT-7;
# a zone that's GMT-6 with DST; and a zone that's always GMT-6.
# From Paul Eggert <eggert@twinsun.com> (1993-11-18):
# Shanks also says there are four zones, but disagrees about the fourth.
# Instead of GMT-6 with DST, he says there's GMT-8 without DST.
# From Alan Perry <alan.perry@eng.sun.com> (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'',
# <URL:http://mexico-travel.com/extra/timezone_eng.html> (1996-01-04).
# From Shanks (1991):
# 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 D
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 max - Apr Sun>=1 2:00 1:00 D
Rule Mexico 1996 max - Oct lastSun 2:00 0 S
#
Rule BajaN 1950 1966 - Apr lastSun 2:00 1:00 D
Rule BajaN 1950 1961 - Sep lastSun 2:00 0 S
Rule BajaN 1961 1966 - Oct lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
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 Mar 30 23:00
-6:00 Mexico C%sT
Zone America/Mazatlan -7:05:40 - LMT 1921 Dec 31 23:54:20
-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 Mar 30 23:00
-6:00 - CST 1942 Apr
-7:00 - MST 1949 Jan 14
-8:00 - PST 1970
-7:00 Mexico M%sT
Zone America/Tijuana -7:48:04 - LMT 1922 Jan 1 0:11:56
-8:00 - PST 1927 Jun 10 23:00
-7:00 - MST 1930 Nov 16
-8:00 - PST 1942 Apr
-7:00 - MST 1949 Jan 14
-8:00 BajaN P%sT 1967 Apr lastSun 2:00
-8:00 US P%sT 1996
-8:00 Mexico P%sT
Zone America/Ensenada -7:46:28 - LMT 1922 Jan 1 0:13:32
-8:00 - PST 1927 Jun 10 23:00
-7:00 - MST 1930 Nov 16
-8:00 - PST 1942 Apr
-7:00 - MST 1949 Jan 14
-8:00 - PST 1996
-8:00 Mexico P%sT
#
# Revillagigedo Is
# no information
###############################################################################
# Anguilla
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Anguilla -4:12:16 - LMT 1912 Mar 2
-4:00 - AST
# Antigua and Barbuda
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Antigua -4:07:12 - LMT 1912 Mar 2
-5:00 - EST 1951
-4:00 - AST
# Bahamas
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Bahamas 1964 max - Oct lastSun 2:00 0 S
Rule Bahamas 1964 1986 - Apr lastSun 2:00 1:00 D
Rule Bahamas 1987 max - Apr Sun>=1 2:00 1:00 D
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Nassau -5:09:24 - LMT 1912 Mar 2
-5:00 Bahamas E%sT
# Barbados
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Barb 1977 only - Jun 12 2:00 1:00 D
Rule Barb 1977 1978 - Oct Sun>=1 2:00 0 S
Rule Barb 1978 1980 - Apr Sun>=15 2:00 1:00 D
Rule Barb 1979 only - Sep 30 2:00 0 S
Rule Barb 1980 only - Sep 25 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Barbados -3:58:28 - LMT 1924 # Bridgetown
-3:58 - BMT 1932 # Bridgetown Mean Time
-4:00 Barb A%sT
# Belize
# Whitman entirely disagrees with Shanks; go with Shanks.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Belize 1918 1942 - Oct Sun>=2 0:00 0:30 HD
Rule Belize 1919 1943 - Feb Sun>=9 0:00 0 S
Rule Belize 1973 only - Dec 5 0:00 1:00 D
Rule Belize 1974 only - Feb 9 0:00 0 S
Rule Belize 1982 only - Dec 18 0:00 1:00 D
Rule Belize 1983 only - Feb 12 0:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Belize -5:52:48 - LMT 1912 Apr
-6:00 Belize C%sT
# Bermuda
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone Atlantic/Bermuda -4:19:04 - LMT 1930 Jan 1 2:00 # Hamilton
-4:00 - AST 1974 Apr 28 2:00
-4:00 Bahamas A%sT
# Cayman Is
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Cayman -5:25:32 - LMT 1890 # Georgetown
-5:07 - KMT 1912 Feb # Kingston Mean Time
-5:00 - EST
# Clipperton
# uninhabited
# Costa Rica
# Shanks gives some very odd dates for 1991, and stops there.
# For now, we won't guess further.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule CR 1979 1980 - Feb lastSun 0:00 1:00 D
Rule CR 1979 1980 - Jun Sun>=1 0:00 0 S
Rule CR 1991 1992 - Jan Sat>=15 0:00 1:00 D
# IATA SSIM (1991-09) says the following was at 1:00; go with Shanks.
Rule CR 1991 only - Jul 1 0:00 0 S
Rule CR 1992 only - Mar 15 0:00 0 S
# There are too many San Joses elsewhere, so we'll use `Costa Rica'.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Costa_Rica -5:36:20 - LMT 1890 # San Jose
-5:36 - SJMT 1921 Jan 15 # San Jose Mean Time
-6:00 CR C%sT
# Coco
# no information; probably like America/Costa_Rica
# Cuba
# From Bob Devine (1988-01-28):
# . . .DST is from 2nd Sunday in May to 2nd Sunday in October since 1981.
# Change at midnight. In 1979 & 1980, started at 3rd Sunday in March
# (I think).
# From U. S. Naval Observatory (1989-01-19):
# CUBA 5 H BEHIND UTC
# CUBA 4 H BEHIND UTC MAR 20 - OCT 8
# From Shanks (1991):
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Cuba 1928 only - Jun 10 0:00 1:00 D
Rule Cuba 1928 only - Oct 10 0:00 0 S
Rule Cuba 1940 1942 - Jun Sun>=1 0:00 1:00 D
Rule Cuba 1940 1942 - Sep Sun>=1 0:00 0 S
Rule Cuba 1945 1946 - Jun Sun>=1 0:00 1:00 D
Rule Cuba 1945 1946 - Sep Sun>=1 0:00 0 S
Rule Cuba 1965 only - Jun 1 0:00 1:00 D
Rule Cuba 1965 only - Sep 30 0:00 0 S
Rule Cuba 1966 only - May 29 0:00 1:00 D
Rule Cuba 1966 only - Oct 2 0:00 0 S
Rule Cuba 1967 only - Apr 8 0:00 1:00 D
Rule Cuba 1967 1968 - Sep Sun>=8 0:00 0 S
Rule Cuba 1968 only - Apr 14 0:00 1:00 D
Rule Cuba 1969 1977 - Apr lastSun 0:00 1:00 D
Rule Cuba 1969 1971 - Oct lastSun 0:00 0 S
Rule Cuba 1972 1974 - Oct 8 0:00 0 S
Rule Cuba 1975 1977 - Oct lastSun 0:00 0 S
Rule Cuba 1978 only - May 7 0:00 1:00 D
Rule Cuba 1978 1980 - Oct Sun>=8 0:00 0 S
Rule Cuba 1979 1980 - Mar Sun>=15 0:00 1:00 D
Rule Cuba 1981 1985 - May Sun>=5 0:00 1:00 D
Rule Cuba 1981 1990 - Oct Sun>=8 0:00 0 S
Rule Cuba 1986 1989 - Mar Sun>=14 0:00 1:00 D
Rule Cuba 1990 max - Apr Sun>=1 0:00 1:00 D
Rule Cuba 1991 1995 - Oct Sun>=8 0:00s 0 S
Rule Cuba 1996 max - Oct Sun>=1 0:00s 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Havana -5:29:28 - LMT 1890
-5:30 - HMT 1925 Jul 19 12:00 # Havana MT
-5:00 Cuba C%sT
# Dominica
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Dominica -4:05:36 - LMT 1911 Jul 1 0:01 # Roseau
-4:00 - AST
# Dominican Republic
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule DR 1966 only - Oct 30 0:00 1:00 D
Rule DR 1967 only - Feb 28 0:00 0 S
Rule DR 1969 1973 - Oct lastSun 0:00 0:30 HD
Rule DR 1970 only - Feb 21 0:00 0 S
Rule DR 1971 only - Jan 20 0:00 0 S
Rule DR 1972 1974 - Jan 21 0:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Santo_Domingo -4:39:36 - LMT 1890
-4:40 - SDMT 1933 Apr 1 12:00 # S. Dom. MT
-5:00 DR E%sT 1974 Oct 27
-4:00 - AST
# El Salvador
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Salv 1987 1988 - May Sun>=1 0:00 1:00 D
Rule Salv 1987 1988 - Sep lastSun 0:00 0 S
# There are too many San Salvadors elsewhere, so we'll use `El Salvador'.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/El_Salvador -5:56:48 - LMT 1921 # San Salvador
-6:00 Salv C%sT
# Grenada
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Grenada -4:07:00 - LMT 1911 Jul # St George's
-4:00 - AST
# Guadeloupe
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Guadeloupe -4:06:08 - LMT 1911 Jun 8 # Pointe a Pitre
-4:00 - AST
# Guatemala
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Guat 1973 only - Nov 25 0:00 1:00 D
Rule Guat 1974 only - Feb 24 0:00 0 S
Rule Guat 1983 only - May 21 0:00 1:00 D
Rule Guat 1983 only - Sep 22 0:00 0 S
Rule Guat 1991 only - Mar 23 0:00 1:00 D
Rule Guat 1991 only - Sep 7 0:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Guatemala -6:02:04 - LMT 1918 Oct 5
-6:00 Guat C%sT
# Haiti
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Haiti 1983 only - May 8 0:00 1:00 D
Rule Haiti 1984 1987 - Apr lastSun 0:00 1:00 D
Rule Haiti 1983 1987 - Oct lastSun 0:00 0 S
# Shanks says AT is 2:00, but IATA SSIM (1991/1996) says 1:00s. Go with IATA.
Rule Haiti 1988 max - Apr Sun>=1 1:00s 1:00 D
Rule Haiti 1988 max - Oct lastSun 1:00s 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Port-au-Prince -4:49:20 - LMT 1890
-4:49 - PPMT 1917 Jan 24 12:00 # P-a-P MT
-5:00 Haiti E%sT
# Honduras
# Shanks says 1921 Jan 1; go with Whitman's more precise Apr 1.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Tegucigalpa -5:48:52 - LMT 1921 Apr
-6:00 Salv C%sT
# Jamaica
# From Bob Devine (1988-01-28):
# Follows US rules.
# From U. S. Naval Observatory (1989-01-19):
# JAMAICA 5 H BEHIND UTC
# From Shanks (1991):
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Jamaica -5:07:12 - LMT 1890 # Kingston
-5:07 - KMT 1912 Feb # Kingston Mean Time
-5:00 - EST 1974 Jan 6 2:00
-5:00 US E%sT 1984
-5:00 - EST
# Martinique
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Martinique -4:04:20 - LMT 1890 # Fort-de-France
-4:04 - FFMT 1911 May # Fort-de-France MT
-4:00 - AST 1980 Apr 6
-4:00 1:00 ADT 1980 Sep 28
-4:00 - AST
# Montserrat
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Montserrat -4:08:52 - LMT 1911 Jul 1 0:01 # Plymouth
-4:00 - AST
# Nicaragua
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Nic 1979 1980 - Mar Sun>=16 0:00 1:00 D
Rule Nic 1979 1980 - Jun Mon>=23 0:00 0 S
Rule Nic 1992 only - Jan 1 4:00 1:00 D
Rule Nic 1992 only - Sep 24 0:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Managua -5:45:08 - LMT 1890
-5:45 - MMT 1934 Jun 23 # Managua Mean Time
-6:00 - CST 1973 May
-5:00 - EST 1975 Feb 16
-6:00 Nic C%sT 1993 Jan 1 4:00
-5:00 - EST
# Panama
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Panama -5:18:08 - LMT 1890
-5:20 - PMT 1908 Apr 22 # Panama Mean Time
-5:00 - EST
# Puerto Rico
# There are too many San Juans elsewhere, so we'll use `Puerto_Rico'.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Puerto_Rico -4:24:25 - LMT 1899 Mar 28 12:00 # San Juan
-4:00 - AST 1942 May 3
-4:00 1:00 AWT 1945 Sep 30 2:00
-4:00 - AST
# St Kitts-Nevis
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/St_Kitts -4:10:52 - LMT 1912 Mar 2 # Basseterre
-4:00 - AST
# St Lucia
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/St_Lucia -4:04:00 - LMT 1890 # Castries
-4:04 - CMT 1912 # Castries Mean Time
-4:00 - AST
# St Pierre and Miquelon
# There are too many St Pierres elsewhere, so we'll use `Miquelon'.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Miquelon -3:44:40 - LMT 1911 May 15 # St Pierre
-4:00 - AST 1980 May
-3:00 Mont PM%sT # Pierre & Miquelon Time
# St Vincent and the Grenadines
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/St_Vincent -4:04:56 - LMT 1890 # Kingstown
-4:05 - KMT 1912 # Kingstown Mean Time
-4:00 - AST
# Turks and Caicos
# From Paul Eggert (1996-11-22):
# Shanks says they use US DST rules, but IATA SSIM (1991/1996)
# says they switch at midnight. Go with IATA SSIM.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule TC 1979 1986 - Apr lastSun 0:00 1:00 D
Rule TC 1979 max - Oct lastSun 0:00 0 S
Rule TC 1987 max - Apr Sun>=1 0:00 1:00 D
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Grand_Turk -4:44:32 - LMT 1890
-5:07 - KMT 1912 Feb # Kingston Mean Time
-5:00 TC E%sT
# British Virgin Is
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Tortola -4:18:28 - LMT 1911 Jul # Road Town
-4:00 - AST
# Virgin Is
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/St_Thomas -4:19:44 - LMT 1911 Jul # Charlotte Amalie
-4:00 - AST
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