#

# DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

#

# This code is free software; you can redistribute it and/or modify it

# under the terms of the GNU General Public License version 2 only, as

# published by the Free Software Foundation.  Oracle designates this

# particular file as subject to the "Classpath" exception as provided

# by Oracle in the LICENSE file that accompanied this code.

#

# This code is distributed in the hope that it will be useful, but WITHOUT

# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

# version 2 for more details (a copy is included in the LICENSE file that

# accompanied this code).

#

# You should have received a copy of the GNU General Public License version

# 2 along with this work; if not, write to the Free Software Foundation,

# Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

#

# Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

# or visit www.oracle.com if you need additional information or have any

# questions.

#

# 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