path: root/share/zoneinfo/datfiles/northamerica

# @(#)northamerica	4.8

###############################################################################

# United States

# 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.
#    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 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
# Aleutians.

# 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:
#	(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 April 1, 1967 until November 30, 1983 (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 November 30, 1983:
#	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.

# 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"
# times).

# 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
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.)

Link	US/Mountain	Navajo

# From Bob Devine (January 28, 1988):
# Michigan didn't observe DST from 1968 to 1973.

Zone	US/Michigan	-5:00	US		E%sT	1968
			-5:00	-		EST	1973
			-5:00	US		E%sT

# 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
			-11:00	-		SST		    # S=Samoa

# Aleutian has a name change.  DST, per Naval Observatory.

Zone	US/Aleutian	-10:00	US		AH%sT	1983 Nov 30
			-10:00	US		HA%sT

# 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
			-10:00	-	HST

# Old names, for S5 users

# Link	LINK-FROM	LINK-TO
# Link	US/Eastern	EST5EDT
# Link	US/Central	CST6CDT
# Link	US/Mountain	MST7MDT
# Link	US/Pacific	PST8PDT
# Link	US/East-Indiana	EST
# Link	US/Arizona	MST
# Link	US/Hawaii	HST

################################################################################

# Canada

# 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
# Canada is doing so.

# 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.

# 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 # No DST as of 1987
Zone	Canada/Mountain		-7:00	Canada		M%sT
Zone	Canada/Pacific		-8:00	Canada		P%sT
Zone	Canada/Yukon		-9:00	Canada		Y%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; 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
# starting date below.

# 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                                 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 (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

###############################################################################

# Jamaica

# From Bob Devine (January 28, 1988):
# Follows US rules.

# From U. S. Naval Observatory (January 19, 1989):
# JAMAICA             5 H  BEHIND UTC

Link	US/Eastern	Jamaica

###############################################################################

# Cuba

# 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
# (I think).

# From U. S. Naval Observatory (January 19, 1989):
# CUBA                5 H  BEHIND UTC
# 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