Howse writes (pp 121-125)4 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, D.C., but in 1872-05 he moved the proposed origin to Greenwich.
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 U.S. 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 U.S. soon followed suit.5
That 1883 transition occurred at 12:00 new time, not at 12:00 old time.6
A good source for time zone historical data in the U.S. is The American Atlas by Thomas G. Shanks.7 Make sure you have the errata sheet; the book is somewhat useless without it. It is the source for most of the pre-1991 U.S. entries below.
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, XIX, Sunday, (Clarke, Irwin, 1947).
For more about the first ten years of DST in the United States, see Robert Garland’s Ten Years of Daylight Saving: From the Pittsburgh Standpoint.8
Shanks says that DST was called “War Time” in the U.S. 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.”
Here is the legal basis for the U.S. federal rules.
All transitions are at 02:00 local time.
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 a link.18 “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.
This was the V-J Day issue of the Clamdigger, a Rowayton, CT newsletter.
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’s 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.
Joseph Gallant, citing George H. Douglas19
It was Robert St. John, not Bob Trout. From his obit in today’s Los Angeles Times:20
…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.
Paul has been careful to use the “U.S.” 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 “U.S.” rules have changed in the latest release, other countries won’t be affected.
# Rule NAME FROM TO - 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 30 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 lastSun 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 SWe 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 U.S. rules in another file.
# Zone NAME STDOFF 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%sTFrom the 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 |
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.
Legal standard time zone names, from 15 U.S.C. § 26021 and forward. First, names up to 1967-04-01 (when most provisions of the Uniform Time Act of 196622 took effect), as explained in sections 263 and 261:
Next, names from 1967-04-01 until 1983-11-30 (the date for public law 98-181):
And after 1983-11-30:
The law doesn’t give abbreviations.
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 a 2001-01-08 heads-up from Rives McDow: public law 106-56423 introduced “Chamorro standard time” for time in Guam and the Northern Marianas. See the file “australasia.” Also see 15 U.S.C. 263.24
HST and HDT are standardized abbreviations for Hawaii-Aleutian standard and daylight times. See the 2008 edition of the U.S. Government Printing Office Style Manual.25
The following was signed into law on 2005-08-08.26
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
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.
According to today’s Huntsville Times27 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.”
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.28
The Monthly Notices of the Royal Astronomical Society29 say 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.
# Rule NAME FROM TO - 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 STDOFF RULES FORMAT [UNTIL]
#STDOFF -4:56:01.6
Zone America/New_York -4:56:02 - LMT 1883 Nov 18 17:00u
-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%sTAlabama, 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
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 “How Chicago Gave America Its Time Zones.”30
Re Wisconsin: Wis. Stat. § 17531 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….
Wisconsin has enacted (nearly eleventh-hour) legislation to get Wis. Stat. § 175 closer in synch with the U.S. Congress’ intent….32
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!)
Assume this practice predates 1970, so Fort Pierre can use America/Chicago.
In 1950s Nashville a public clock had dueling faces, one for conservatives and the other for liberals; the two sides didn’t agree about the time of day. I haven’t found a photo of this clock, nor have I tracked down the TIME magazine report cited below, but here’s the story as told by the late American journalist John Seigenthaler, who was there:
The two [newspaper] owners held strongly contrasting political and ideological views. Evans was a New South liberal, Stahlman an Old South conservative, and their two papers frequently clashed editorially, often on the same day…. In the 1950s as the state legislature was grappling with the question of whether to approve daylight saving time for the entire state, TIME magazine reported:
“The Nashville Banner and The Nashville Tennessean rarely agree on anything but the time of day — and last week they couldn’t agree on that.”
It was all too true. The clock on the front of the building had two faces — The Tennessean side of the building facing west, the other, east. When it was high noon Banner time, it was 11 a.m. Tennessean time.
John Seigenthaler, “For 100 years, Tennessean had it covered.”33
# Rule NAME FROM TO - 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 STDOFF RULES FORMAT [UNTIL]
Zone America/Chicago -5:50:36 - LMT 1883 Nov 18 18:00u
-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 19:00u
-7:00 US M%sT 1992 Oct 25 2:00
-6:00 US C%sTMorton County, ND switched from mountain to central time on 2003-10-26, except for the area around Mandan which was already central time.34 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.35
Zone America/North_Dakota/New_Salem -6:45:39 - LMT 1883 Nov 18 19:00u
-7:00 US M%sT 2003 Oct 26 2:00
-6:00 US C%sT…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).36 37
…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 19:00u
-7:00 US M%sT 2010 Nov 7 2:00
-6:00 US C%sTColorado, 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
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.38
# Rule NAME FROM TO - 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 STDOFF RULES FORMAT [UNTIL]
Zone America/Denver -6:59:56 - LMT 1883 Nov 18 19:00u
-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%sTCalifornia, 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
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.)39
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 the fallback transition earlier.40
In response:41
Governor Warren received a torrent of objecting mail, and it is not too much to speculate that the objections to Daylight Saving Time were one important factor in the defeat of the Dewey–Warren Presidential ticket in California.
On December 8 the governor exercised the option, setting the date to January 1 (L.A. Times 1948-12-09). The transition time was 02:00 (L.A. Times 1949-01-01).
Despite the controversy, in 1949 California voters approved Proposition 12, which established DST from April’s last Sunday at 01:00 until September’s last Sunday at 02:00.42 This was amended by 1962’s Proposition 6, which changed the fall-back date to October’s last Sunday.43
# Rule NAME FROM TO - IN ON AT SAVE LETTER
Rule CA 1948 only - Mar 14 2:01 1:00 D
Rule CA 1949 only - Jan 1 2:00 0 S
Rule CA 1950 1966 - Apr lastSun 1:00 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 STDOFF RULES FORMAT [UNTIL]
Zone America/Los_Angeles -7:52:58 - LMT 1883 Nov 18 20:00u
-8:00 US P%sT 1946
-8:00 CA P%sT 1967
-8:00 US P%sTAK%sT is the modern abbreviation for -09 per the U.S. Naval Observatory.
Howse44 writes that Alaska switched from the Julian to the Gregorian calendar, and from east-of-GMT to west-of-GMT days, when the U.S. bought it from Russia. On Friday, 1867-10-18 (Gregorian), at precisely 15:30 local time, the Russian forts and fleet at Sitka fired salutes to mark the ceremony of formal transfer.45 Sitka workers did not change their calendars until Sunday, 1867-10-20, and so celebrated two Sundays that week.46 Include only the time zone part of this transition, ignoring the switch from Julian to Gregorian, since we can’t represent the Julian calendar.
As far as we know, of the locations mentioned below only Sitka was permanently inhabited in 1867 by anyone using either calendar. (Yakutat was colonized by the Russians in 1799, but the settlement was destroyed in 1805 by a Yakutat-kon war party.) Many of Alaska’s inhabitants were unaware of the U.S. acquisition of Alaska, much less of any calendar or time change. However, the Russian-influenced part of Alaska did observe Russian time, and it is more accurate to model this than to ignore it. The database format requires an exact transition time; use the Russian salute as a somewhat-arbitrary time for the formal transfer of control for all of Alaska. Sitka’s UTC offset is -9:01:13; adjust its 15:30 to the local times of other Alaskan locations so that they change simultaneously.
One opinion of the early 1980s turmoil in Alaska over time zones and daylight saving time appeared as graffiti on a Juneau airport wall: “Welcome to Juneau. Please turn your watch back to the 19th century.”47
Steve Ferguson (2011-01-31) referred to another source.48
Here’s database-relevant material from that article:
On September 20 [1979]…DOT…officials decreed that on April 27, 1980, Juneau and other nearby communities would move to Yukon Time. Sitka, Petersburg, Wrangell, and Ketchikan, however, would remain on Pacific Time.
…on September 22, 1980, DOT Secretary Neil E. Goldschmidt rescinded the Department’s September 1979 decision. Juneau and other communities in northern Southeast reverted to Pacific Time on October 26.
On October 28 [1983]…the Metlakatla Indian Community Council voted unanimously to keep the reservation on Pacific Time.
According to DOT official Joanne Petrie, Indian reservations are not bound to follow time zones imposed by neighboring jurisdictions.
(The last is consistent with how the database now handles the Navajo Nation.)
I just spoke by phone with a staff member at the Metlakatla Indian Community office using contact information available online.49 It’s shortly after 1:00 here on the east coast of the United States; the staffer said it was shortly after 10:00 there. When I asked whether that meant they were on Pacific time, they said no — they were on their own time. I asked about daylight saving; they said it wasn’t used. I did not inquire about practices in the past.
For lack of better information, assume that Metlakatla’s abandonment of use of daylight saving resulted from the 1983 vote.
It seems Metlakatla did go off PST on Sunday, November 1, changing their time to AKST and are going to follow Alaska’s DST, switching between AKST and AKDT from now on…50
The Metlakatla community in Alaska has decided not to change its clock back an hour starting on November 4th, 2018 (day before yesterday). They will be gmtoff=-28800 year-round.51
In a 2018-12-11 special election, Metlakatla voted to go back to Alaska time (including daylight saving time) starting next year.52
Per an announcement on the Metlakatla community’s official Facebook page, the “fall back” will be on Sunday 2019-01-20 at 02:00.53 So they won’t be waiting for Alaska to join them on 2019-03-10, but will rather change their clocks twice in seven weeks.
America/Adak is for the Aleutian Islands that are part of Alaska and are west of 169.5° W.
# Zone NAME STDOFF RULES FORMAT [UNTIL]
Zone America/Juneau 15:02:19 - LMT 1867 Oct 19 15:33:32
-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 1980 Apr 27 2:00
-9:00 US Y%sT 1980 Oct 26 2:00
-8:00 US P%sT 1983 Oct 30 2:00
-9:00 US Y%sT 1983 Nov 30
-9:00 US AK%sT
Zone America/Sitka 14:58:47 - LMT 1867 Oct 19 15:30
-9:01:13 - 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 Y%sT 1983 Nov 30
-9:00 US AK%sT
Zone America/Metlakatla 15:13:42 - LMT 1867 Oct 19 15:44:55
-8:46:18 - 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
-8:00 - PST 2015 Nov 1 2:00
-9:00 US AK%sT 2018 Nov 4 2:00
-8:00 - PST 2019 Jan 20 2:00
-9:00 US AK%sT
Zone America/Yakutat 14:41:05 - LMT 1867 Oct 19 15:12:18
-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 Nov 30
-9:00 US AK%sT
Zone America/Anchorage 14:00:24 - LMT 1867 Oct 19 14:31:37
-9:59:36 - LMT 1900 Aug 20 12:00
-10:00 - AST 1942
-10:00 US A%sT 1967 Apr
-10:00 - AHST 1969
-10:00 US AH%sT 1983 Oct 30 2:00
-9:00 US Y%sT 1983 Nov 30
-9:00 US AK%sT
Zone America/Nome 12:58:22 - LMT 1867 Oct 19 13:29:35
-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 Y%sT 1983 Nov 30
-9:00 US AK%sT
Zone America/Adak 12:13:22 - LMT 1867 Oct 19 12:44:35
-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 AH%sT 1983 Nov 30
-10:00 US H%sTThe following switches don’t make our 1970 cutoff.
Kiska observed Tokyo date and time during Japanese occupation from 1942-06-06 to 1943-07-29, and similarly for Attu from 1942-06-07 to 1943-05-29 (all dates American). Both islands are now uninhabited.
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.
In e-mail, 2004-11-02, Ray Hudson, historian/liaison to the Unalaska Historic Preservation Commission, provided this information, which suggests that Unalaska deviated from statutory time from early 1967 possibly until 1983:
Except for St. Paul and Akutan, Unalaska is the only important location not on Alaska Standard Time. The following resolution was made by William Robinson and seconded by Henry Swanson: Be it resolved that the City of Unalaska hereby goes to Alaska Standard Time as of midnight Friday, January 13, 1967 (1 A.M. Saturday, January 14, Alaska Standard Time.) This resolution was passed with three votes for and one against.
Minutes of the Unalaska City Council Meeting, January 10, 1967
Schmitt and Cox54 indicate that standard time was adopted effective noon, January 13, 1896 (page 218), that in “1933, the Legislature decreed daylight saving for the period between the last Sunday of each April and the last Sunday of each September, but less than a month later repealed the act,” (page 220), that year-round daylight saving time was in effect from 1942-02-09 to 1945-09-30 (page 221, with no time of day given for when clocks changed) and that clocks were changed by 30 minutes effective the second Sunday of June, 1947 (page 219, with no time of day given for when clocks changed). A footnote for the 1933 changes cites Session Laws of Hawaii 1933, “Act. 90 (approved 26 Apr. 1933) and Act 163 (approved 21 May 1933).”
Act 90…At 2 o’clock ante meridian of the last Sunday in April of each year, the standard time of this Territory shall be advanced one hour…This Act shall take effect upon its approval. Approved this 26th day of April, A. D. 1933. LAWRENCE M JUDD, Governor of the Territory of Hawaii.
1933 Haw. Sess. Laws 8555
Act 163…Act 90 of the Session Laws of 1933 is hereby repealed…This Act shall take effect upon its approval, upon which date the standard time of this Territory shall be restored to that existing immediately prior to the taking effect of said Act 90. Approved this 21st day of May, A. D. 1933. LAWRENCE M. JUDD, Governor of the Territory of Hawaii.
1933 Haw. Sess. Laws 17256
Note that 1933-05-21 was a Sunday. We’re left to guess the time of day when Act 163 was approved; guess noon.
# Zone NAME STDOFF RULES FORMAT [UNTIL]
Zone Pacific/Honolulu -10:31:26 - LMT 1896 Jan 13 12:00
-10:30 - HST 1933 Apr 30 2:00
-10:30 1:00 HDT 1933 May 21 12:00
-10:30 US H%sT 1947 Jun 8 2:00
-10:00 - HSTNow we turn to U.S. areas that have diverged from the consensus since 1970.
Arizona mostly uses MST.
Between 1944-01-01 and 1944-04-01 the State of Arizona used standard time, but by federal law railroads, airlines, bus lines, military personnel, and some engaged in interstate commerce continued to observe war (i.e., daylight saving) time. The 1944-03-17 Phoenix Gazette says that was the date the law changed, and that 04-01 was the date the state’s clocks would change. In 1945 the State of Arizona used standard time all year, again with exceptions only as mandated by federal law.57 Arizona observed DST in 1967, but repealed DST effective 1968-03-21.58
Shanks says the 1944 experiment came to an end on 1944-03-17. Go with the Arizona State Library instead.
# Zone NAME STDOFF RULES FORMAT [UNTIL]
Zone America/Phoenix -7:28:18 - LMT 1883 Nov 18 19:00u
-7:00 US M%sT 1944 Jan 1 0:01
-7:00 - MST 1944 Apr 1 0:01
-7:00 US M%sT 1944 Oct 1 0:01
-7:00 - MST 1967
-7:00 US M%sT 1968 Mar 21
-7:00 - MSTA writer from the Inter Tribal Council of Arizona, Inc., notes in private correspondence dated 1987-12-28 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.)
See America/Denver for a zone appropriate for the Navajo Nation.
Southern Idaho (Ada, Adams, Bannock, Bear Lake, Bingham, Blaine, Boise, Bonneville, Butte, Camas, Canyon, Caribou, Cassia, Clark, Custer, Elmore, Franklin, Fremont, Gem, Gooding, Jefferson, Jerome, Lemhi, Lincoln, Madison, Minidoka, Oneida, Owyhee, Payette, Power, Teton, Twin Falls, Valley, Washington counties, and the southern quarter of Idaho county) and eastern Oregon (most of Malheur County) switched four weeks late in 1974.
# Zone NAME STDOFF RULES FORMAT [UNTIL]
Zone America/Boise -7:44:49 - LMT 1883 Nov 18 20:00u
-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%sTFor a map of Indiana’s time zone regions, see Wikipedia.59
A brief but entertaining history of time in Indiana describes a 1949 debate in the Indiana House where city legislators (who favored “fast time”) tussled with farm legislators (who didn’t) over a bill to outlaw DST:
Lacking enough votes, the city faction tries to filibuster until time runs out on the session at midnight, but rural champion Rep. Herbert Copeland, R-Madison, leans over the gallery railing and forces the official clock back to 9 p.m., breaking it in the process. The clock sticks on 9 as the debate rages on into the night. The filibuster finally dies out and the bill passes, while outside the chamber, clocks read 3:30 a.m. In the end, it doesn’t matter which side won. The law has no enforcement powers and is simply ignored by fast-time communities.60
Since 1970, most of Indiana has been like America/Indiana/Indianapolis, with the following exceptions:
Shanks partitioned Indiana into 345 regions, each with its own time history, and wrote “Even newspaper reports present contradictory information.” Those Hoosiers! Such a flighty and changeable people! Fortunately, most of the complexity occurred before our cutoff date of 1970.
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.”
DOT is relocating the time zone boundary in Indiana to move Starke, Pulaski, Knox, Daviess, Martin, Pike, Dubois, and Perry Counties from the Eastern Time Zone to the Central Time Zone…. The effective date of this rule is 2 a.m. EST Sunday, April 2, 2006, which is the changeover date from standard time to Daylight Saving Time.61
Strictly speaking, this meant the affected counties changed their clocks twice that night, but this obviously was in error. The intent was that 01:59:59 EST be followed by 02:00:00 CDT.
The Associated Press has been reporting that Pulaski County, Indiana is going to switch from Central to Eastern Time on March 11, 2007…62
# Rule NAME FROM TO - 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 STDOFF RULES FORMAT [UNTIL]
Zone America/Indiana/Indianapolis -5:44:38 - LMT 1883 Nov 18 18:00u
-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 2006
-5:00 US E%sTEastern Crawford County, Indiana, left its clocks alone in 1974, as well as from 1976 through 2005.
# Rule NAME FROM TO - 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 STDOFF RULES FORMAT [UNTIL]
Zone America/Indiana/Marengo -5:45:23 - LMT 1883 Nov 18 18:00u
-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 2006
-5:00 US E%sTDaviess, Dubois, Knox, and Martin Counties, Indiana, switched from eastern to central time in April 2006, then switched back in November 2007.
# Rule NAME FROM TO - IN ON AT SAVE LETTER
Rule Vincennes 1946 only - Apr lastSun 2:00 1:00 D
Rule Vincennes 1946 only - Sep lastSun 2:00 0 S
Rule Vincennes 1953 1954 - Apr lastSun 2:00 1:00 D
Rule Vincennes 1953 1959 - Sep lastSun 2:00 0 S
Rule Vincennes 1955 only - May 1 0:00 1:00 D
Rule Vincennes 1956 1963 - Apr lastSun 2:00 1:00 D
Rule Vincennes 1960 only - Oct lastSun 2:00 0 S
Rule Vincennes 1961 only - Sep lastSun 2:00 0 S
Rule Vincennes 1962 1963 - Oct lastSun 2:00 0 S
# Zone NAME STDOFF RULES FORMAT [UNTIL]
Zone America/Indiana/Vincennes -5:50:07 - LMT 1883 Nov 18 18:00u
-6:00 US C%sT 1946
-6:00 Vincennes C%sT 1964 Apr 26 2:00
-5:00 - EST 1969
-5:00 US E%sT 1971
-5:00 - EST 2006 Apr 2 2:00
-6:00 US C%sT 2007 Nov 4 2:00
-5:00 US E%sTPerry County, Indiana, switched from eastern to central time in April 2006.
The Indianapolis News, Friday 27 October 1967 states that Perry County returned to CST. It went again to EST on 27 April 1969, as documented by the Indianapolis Star of Saturday 26 April.
# Rule NAME FROM TO - IN ON AT SAVE LETTER
Rule Perry 1955 only - May 1 0:00 1:00 D
Rule Perry 1955 1960 - Sep lastSun 2:00 0 S
Rule Perry 1956 1963 - Apr lastSun 2:00 1:00 D
Rule Perry 1961 1963 - Oct lastSun 2:00 0 S
# Zone NAME STDOFF RULES FORMAT [UNTIL]
Zone America/Indiana/Tell_City -5:47:03 - LMT 1883 Nov 18 18:00u
-6:00 US C%sT 1946
-6:00 Perry C%sT 1964 Apr 26 2:00
-5:00 - EST 1967 Oct 29 2:00
-6:00 US C%sT 1969 Apr 27 2:00
-5:00 US E%sT 1971
-5:00 - EST 2006 Apr 2 2:00
-6:00 US C%sTPike County, Indiana moved from central to eastern time in 1977, then switched back in 2006, then switched back again in 2007.
# Rule NAME FROM TO - IN ON AT SAVE LETTER
Rule Pike 1955 only - May 1 0:00 1:00 D
Rule Pike 1955 1960 - Sep lastSun 2:00 0 S
Rule Pike 1956 1964 - Apr lastSun 2:00 1:00 D
Rule Pike 1961 1964 - Oct lastSun 2:00 0 S
# Zone NAME STDOFF RULES FORMAT [UNTIL]
Zone America/Indiana/Petersburg -5:49:07 - LMT 1883 Nov 18 18:00u
-6:00 US C%sT 1955
-6:00 Pike C%sT 1965 Apr 25 2:00
-5:00 - EST 1966 Oct 30 2:00
-6:00 US C%sT 1977 Oct 30 2:00
-5:00 - EST 2006 Apr 2 2:00
-6:00 US C%sT 2007 Nov 4 2:00
-5:00 US E%sTStarke County, Indiana moved from central to eastern time in 1991, then switched back in 2006.
Starke County switched from Central time to Eastern time as of 1991-10-27.63
# Rule NAME FROM TO - 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 STDOFF RULES FORMAT [UNTIL]
Zone America/Indiana/Knox -5:46:30 - LMT 1883 Nov 18 18:00u
-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 2006 Apr 2 2:00
-6:00 US C%sTPulaski County, Indiana, switched from eastern to central time in April 2006 and then switched back in March 2007.
# Rule NAME FROM TO - IN ON AT SAVE LETTER
Rule Pulaski 1946 1960 - Apr lastSun 2:00 1:00 D
Rule Pulaski 1946 1954 - Sep lastSun 2:00 0 S
Rule Pulaski 1955 1956 - Oct lastSun 2:00 0 S
Rule Pulaski 1957 1960 - Sep lastSun 2:00 0 S
# Zone NAME STDOFF RULES FORMAT [UNTIL]
Zone America/Indiana/Winamac -5:46:25 - LMT 1883 Nov 18 18:00u
-6:00 US C%sT 1946
-6:00 Pulaski C%sT 1961 Apr 30 2:00
-5:00 - EST 1969
-5:00 US E%sT 1971
-5:00 - EST 2006 Apr 2 2:00
-6:00 US C%sT 2007 Mar 11 2:00
-5:00 US E%sTSwitzerland County, Indiana, did not observe DST from 1973 through 2005.
# Zone NAME STDOFF RULES FORMAT [UNTIL]
Zone America/Indiana/Vevay -5:40:16 - LMT 1883 Nov 18 18:00u
-6:00 US C%sT 1954 Apr 25 2:00
-5:00 - EST 1969
-5:00 US E%sT 1973
-5:00 - EST 2006
-5:00 US E%sTThe Louisville & Nashville Railroad’s 1883-11-18 change occurred at 10:00 old local time; trains were supposed to come to a standstill for precisely 18 minutes. See Bartky Fig. 1 (page 50).64 It is not clear how this matched civil time in Louisville, so for now continue to assume Louisville switched at noon new local time, like New York.
From the contemporary source given by Alois Treindl, the switch in Louisville on 1946-04-28 was on 00:01.
That source was the Louisville Courier-Journal, 1946-04-27, p 4.65 Shanks gives 02:00 for all 20th-century transition times in Louisville. Evidently this is wrong for spring 1946. Although also likely wrong for other dates, we have no data.
Part of Kentucky left its clocks alone in 1974. This also includes Clark, Floyd, and Harrison counties in Indiana.
# Rule NAME FROM TO - 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 only - Apr lastSun 2:00 1:00 D
Rule Louisville 1941 only - Sep lastSun 2:00 0 S
Rule Louisville 1946 only - Apr lastSun 0:01 1:00 D
Rule Louisville 1946 only - Jun 2 2:00 0 S
Rule Louisville 1950 1961 - Apr lastSun 2:00 1:00 D
Rule Louisville 1950 1955 - Sep lastSun 2:00 0 S
Rule Louisville 1956 1961 - Oct lastSun 2:00 0 S
# Zone NAME STDOFF RULES FORMAT [UNTIL]
Zone America/Kentucky/Louisville -5:43:02 - LMT 1883 Nov 18 18:00u
-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%sTWayne County, Kentucky
From Lake Cumberland Life via WKYM-101.7:66
Clinton County has joined Wayne County in asking the DoT to change from the Central to the Eastern time zone…. The Wayne County government made the same request in December. And while Russell County officials have not taken action, the majority of respondents to a poll conducted there in August indicated they would like to change to “fast time” also. The three Lake Cumberland counties are the farthest east of any U.S. location in the Central time zone.
After prolonged debate, and despite continuing deep differences of opinion, Wayne County (central Kentucky) is switching from Central (-0600) to Eastern (-0500) time. They won’t “fall back” this year.67
The final rule was published as 65 Fed. Reg. 50154.68
Zone America/Kentucky/Monticello -5:39:24 - LMT 1883 Nov 18 18:00u
-6:00 US C%sT 1946
-6:00 - CST 1968
-6:00 US C%sT 2000 Oct 29 2:00
-5:00 US E%sTHere are all the changes in the U.S. since 1985.
We don’t know where the line used to be within Kearny County, KS, so omit that change for now. See America/Indiana/Knox for the Starke County, IN change. See America/North_Dakota/Center for the Oliver County, ND change. West Wendover, NV officially switched from Pacific to mountain time on 1999-10-31. See the Federal Register.69 However, the Federal Register says that West Wendover already operated on mountain time, and the rule merely made this official; hence a separate tz entry is not needed.
Michigan didn’t observe DST from 1968 to 1973.
Shanks70 writes that Michigan started using standard time on 1885-09-18, but Howse71 writes (pp 124-125, referring to Popular Astronomy, 1901-01) 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.
Garland72 writes “Cleveland and Detroit advanced their clocks one hour in 1914.” This change is not in Shanks. We have no more info, so omit this for now.
Due to a complicated set of legal maneuvers, in 1967 Michigan did not start daylight saving time when the rest of the U.S. did. Instead, it began DST on Jun 14 at 00:01. This was big news: the Detroit Free Press reported it at the top of Page 1 on 1967-06-14, in an article “State Adjusting to Switch to Fast Time” by Gary Blonston, above an article about Thurgood Marshall’s confirmation to the U.S. Supreme Court. Although Shanks says Detroit observed DST until 1967-10-29 00:01, that time of day seems to be incorrect, as the Free Press later said DST ended in Michigan at the same time as the rest of the U.S. Also, although Shanks reports no DST in Detroit in 1968, it did observe DST that year; in the November 1968 election Michigan voters narrowly repealed DST, effective 1969.
Most of Michigan observed DST from 1973 on, but was a bit late in 1975.
# Rule NAME FROM TO - 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
# Zone NAME STDOFF 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 1967 Jun 14 0:01
-5:00 US E%sT 1969
-5:00 - EST 1973
-5:00 US E%sT 1975
-5:00 - EST 1975 Apr 27 2:00
-5:00 US E%sTDickinson, Gogebic, Iron, and Menominee Counties, Michigan, switched from EST to CST/CDT in 1973.
# Rule NAME FROM TO - 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 STDOFF 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%sTAdministered by the U.S. Fish and Wildlife Service, claimed by U.S. under the provisions of the 1856 Guano Islands Act.73 Also claimed by Haiti. Occupied 1857/1900 by the Navassa Phosphate Co. U.S. lighthouse 1917/1996-09. Currently uninhabited. See “An Isle Rich in Guana and Discord,”74 citing The Great Guano Rush.75
Unless otherwise specified, the source for data through 1990 is The International Atlas.76 Unfortunately this book contains many errors and cites no sources.
Many years ago Gwillim Law wrote that a good source for time zone data was the International Air Transport Association’s Standard Schedules Information Manual, published semiannually.77 Law sent in several helpful summaries of the IATA’s data after 1990. Except where otherwise noted, IATA SSIM is the source for entries after 1990.
Other sources occasionally used include: