###############################################################################
# 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, October 26, 1974
# and Sunday, October 27, 1974 editions of the Washington Post.
# From seismo!munnari!kre:
# I recall also being told by someone once that Canada didn't have
# the DST variations in 74/75 that the US did, but I am not nearly
# sure enough of this to add anything.
# From Arthur David Olson:
# The above has been confirmed by Bob Devine; we'll go with it here.
# 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 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 - 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 (January 28, 1988):
# ...Alaska (and Hawaii) had the timezone names changed in 1967.
# 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 U. S. Naval Observatory (January 19, 1989):
# 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 (January 21, 1989):
# 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
# From Arthur David Olson (February 13, 1988):
# 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 April 1, 1967 (when most provisions of the Uniform Time Act of 1966
# took effect), as explained in sections 263 and 261:
# United States standard eastern time
# United States standard mountain time
# United States standard central time
# United States standard Pacific time
# United States standard Alaska time
# Next, names from April 1, 1967 until November 30, 1983 (the date for
# Alaska-Hawaii standard time
# And after November 30, 1983:
# Hawaii-Aleutian standard time
# The law doesn't give abbreviations.
# Easy stuff first--including Alaska, where we ignore history (since we
# can't tell if we should give Yukon time or Alaska-Hawaii time for "old"
# Zone NAME GMTOFF RULES/SAVE FORMAT [UNTIL]
Zone US/Eastern -5:00 US E%sT
Zone US/Central -6:00 US C%sT
Zone US/Mountain -7:00 US M%sT
Zone US/Pacific -8:00 US P%sT
Zone US/Alaska -9:00 US AK%sT # Abbreviation per USNO
# Mainland US areas that are always Standard as of 1986.
Zone US/East-Indiana -5:00 US E%sT 1946
-5:00 - EST # Always EST as of 1986
# From Arthur David Olson (October 28, 1991):
# An article on page A3 of the Sunday, October 27, 1991 Washington Post
# notes that Starke County switched from Central time to Eastern time as of
Zone US/Indiana-Starke -6:00 US C%sT 1991 Oct 27 2:00
-5:00 - EST # Always EST as of 1991
Zone US/Arizona -7:00 US M%sT 1946
-7:00 - MST # Always MST as of 1986
# From Arthur David Olson (February 13, 1988):
# However. . .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.)
# From Bob Devine (January 28, 1988):
# Michigan didn't observe DST from 1968 to 1973.
Zone US/Michigan -5:00 US E%sT 1968
# Samoa just changes names. No DST, per Naval Observatory.
Zone US/Samoa -11:00 - NST 1967 Apr 1 # N=Nome
-11:00 - BST 1983 Nov 30 # B=Bering
# Aleutian has a name change. DST, per Naval Observatory.
Zone US/Aleutian -10:00 US AH%sT 1983 Nov 30
# From Arthur David Olson:
# And then there's Hawaii.
# DST was observed for one day in 1933;
# Standard time was change by half an hour in 1947;
# it's always standard as of 1986.
Zone US/Hawaii -10:30 US H%sT 1933 Apr 30 2:00
-10:30 1:00 HDT 1933 May 1 2:00
-10:30 US H%sT 1947 Jun 8 2:00
# Old names, for S5 users
# Link US/Eastern EST5EDT
# Link US/Central CST6CDT
# Link US/Mountain MST7MDT
# Link US/Pacific PST8PDT
# Link US/East-Indiana EST
################################################################################
# Canada is reportedly lots easier than the US--leastways since 1951.
# I don't know what they did before then.
# 4.3BSD claims that it's perfectly regular.
# According to a posting in "comp.bugs.misc", "comp.unix.wizards", etc.
# on February 8, 1987, by Dave Sherman of the Law Society of Upper Canada,
# "...Canada (well, Ontario and at least some of the other provinces) are
# adopting the new daylight savings time rules...". We assume all of
# From Bob Devine (January 28, 1988):
# All of Canada did have DST from your first rule except Saskatchewan.
# Which parts did not observe DST is hard to pinpoint but most of the
# province follows the rules.
# NOTE: those that didn't have DST for that rule, also
# probably did not have it for several years previous.
# From U. S. Naval Observatory (January 19, 1989):
# CANADA NEW FDL 3.5H BEHIND UTC ST.JOHN'S
# CANADA NEW FDL 1.5H BEHIND UTC APR 3 - OCT 29
# CANADA ATLANTIC 4 H BEHIND UTC HALIFAX
# CANADA ATLANTIC 3 H BEHIND UTC APR 3 - OCT 29
# CANADA EASTERN 5 H BEHIND UTC TORONTO, MONTREAL, OTTAWA
# CANADA EASTERN 4 H BEHIND UTC APR 3 - OCT 29
# CANADA CENTRAL 6 H BEHIND UTC REGINA, WINNIPEG
# CANADA CENTRAL 5 H BEHIND UTC APR 3 - OCT 29
# CANADA MOUNTAIN 7 H BEHIND UTC CALGARY, EDMONTON
# CANADA MOUNTAIN 6 H BEHIND UTC APR 3 - OCT 29
# CANADA PACIFIC 8 H BEHIND UTC VANCOUVER
# CANADA PACIFIC 7 H BEHIND UTC APR 3 - OCT 29
# CANADA YUKON SAME AS PACIFIC DAWSON
# From Arthur David Olson (January 21, 1989):
# April 3 fell on a Sunday in 1988; October 29 fell on a Sunday in 1989. Ahem.
# Note claim that there's double DST in Newfoundland and that Yukon should
# be same as Pacific. Stick with rules posted in 1988 until more authoritative
# information is available.
# From W. Jones (jones@skdad.usask.ca) (November 6, 1992):
# 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.
# Here's how I would summarize things. Establish a "Saskatchewan" CST
# time zone, and note that it officially exists as of 15 April 1966. Any
# current exceptions can put themselves in the "Mountain" zone, since
# those are the rules they follow. Any past exceptions can be forgotten,
# since that's what those who live here have done.
# From Arthur David Olson (November 21, 1992):
# East-Saskatchewan kept to avoid problems for folks using that zone by name;
# plain Saskatchewan added.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Canada 1969 max - Oct lastSun 2:00 0 S
Rule Canada 1969 1986 - Apr lastSun 2:00 1:00 D
Rule Canada 1987 max - Apr Sun>=1 2:00 1:00 D
# Zone NAME GMTOFF RULES/SAVE FORMAT [UNTIL]
# Bob Devine says that DST *is* observed in Newfoundland
Zone Canada/Newfoundland -3:30 Canada N%sT
Zone Canada/Atlantic -4:00 Canada A%sT
Zone Canada/Eastern -5:00 Canada E%sT
Zone Canada/Central -6:00 Canada C%sT
Zone Canada/East-Saskatchewan -6:00 - CST # see above
Zone Canada/Saskatchewan -6:00 - CST # see above
Zone Canada/Mountain -7:00 Canada M%sT
Zone Canada/Pacific -8:00 Canada P%sT
Zone Canada/Yukon -9:00 Canada Y%sT
###############################################################################
# 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; Mexico/BajaSur is for "Baja California Sur and N. Pacific
# Coast (States of Sinaloa and Sonora)."
# From Bob Devine (January 28, 1988):
# 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 (February 13, 1988)
# Since the 1981 starting date is only "probable," we'll keep the 1987
# From U. S. Naval Observatory (January 19, 1989):
# 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 PARALLAL APR 3
# MEXICO BAJA CAL N - OCT 29
# MEXICO BAJA CAL N 7 H BEHIND UTC ABOVE 28TH PARALLAL APR 3
# MEXICO BAJA CAL N - 0CT 29
# MEXICO 6 H BEHIND UTC STATES OF DURANGO,
# MEXICO COAHUILA, NUEVO LEON,
# 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
# From Arthur David Olson (January 21, 1989):
# 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.
# Wait for more authoritative information before changing.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Mexico 1987 max - Oct lastSun 2:00 0 S
Rule Mexico 1987 max - Apr Sun>=1 2:00 1:00 D
# Zone NAME GMTOFF RULES/SAVE FORMAT [UNTIL]
Zone Mexico/BajaNorte -8:00 Mexico P%sT
Zone Mexico/BajaSur -7:00 - MST
Zone Mexico/General -6:00 - CST
###############################################################################
# From Bob Devine (January 28, 1988):
# From U. S. Naval Observatory (January 19, 1989):
###############################################################################
# From Bob Devine (January 28, 1988):
# . . .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
# From U. S. Naval Observatory (January 19, 1989):
# CUBA 4 H BEHIND UTC MAR 20 - OCT 8
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Cuba 1979 1980 - Mar Sun>=15 0:00 1:00 D
Rule Cuba 1979 1980 - Oct Sun>=8 0:00 0 S
Rule Cuba 1981 max - May Sun>=8 0:00 1:00 D
Rule Cuba 1981 max - Oct Sun>=8 0:00 0 S
# Zone NAME GMTOFF RULES/SAVE FORMAT
Zone Cuba -5:00 Cuba C%sT
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