# %W%

# 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.

# Note also this 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."
# The above has been confirmed by Bob Devine; we'll go with it here.

# 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

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

# New names

# 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/Yukon	-9:00	US		Y%sT

# 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

# 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."

Link	US/Mountain	Navajo

# Bob Devine notes that "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

# 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

# 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 Stnadard 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.

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

# 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.

# 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:
# 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 to 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:
# Since the 1981 starting date is only "probable," we'll keep the 1987
# starting date below.

# 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 (February 10, 1988):
#	JAMAICA             5 H BEHIND UTC IN WINTER
#	JAMAICA             4 H BEHIND UTC APR 29 - OCT 29

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 (February 10, 1988):
#	CUBA                5 H BEHIND UTC IN WINTER
#	CUBA                4 H BEHIND UTC MAY 8 - 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
