Time Zone Changes in 2018

Paul Eggert (2018-05-27):

Unless otherwise specified, the source for data through 1990 is:
Thomas G. Shanks and Rique Pottenger, The International Atlas (6th edition),
San Diego: ACS Publications, Inc. (2003).
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 (IATA SSIM),
published semiannually.  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.

Another source occasionally used is Edward W. Whitman, World Time Differences,
Whitman Publishing Co, 2 Niagara Av, Ealing, London (undated), which
I found in the UCLA library.

For data circa 1899, a common source is:
Milne J. Civil time. Geogr J. 1899 Feb;13(2):173-94.
https://www.jstor.org/stable/1774359

For the 1911/1912 establishment of standard time in French possessions, see:
Société Française de Physique, Recueil de constantes physiques (1913),
page 752, 18b.

European-style abbreviations are commonly used along the Mediterranean.
For sub-Saharan Africa abbreviations were less standardized.
Previous editions of this database used WAT, CAT, SAT, and EAT
for UT +00 through +03, respectively,
but in 1997 Mark R V Murray reported that
'SAST' is the official abbreviation for +02 in the country of South Africa,
'CAT' is commonly used for +02 in countries north of South Africa, and
'WAT' is probably the best name for +01, as the common phrase for
the area that includes Nigeria is "West Africa".

To summarize, the following abbreviations seemed to have some currency:
+00	GMT	Greenwich Mean Time
+02	CAT	Central Africa Time
+02	SAST	South Africa Standard Time
and Murray suggested the following abbreviation:
+01	WAT	West Africa Time
Murray's suggestion seems to have caught on in news reports and the like.
I vaguely recall 'WAT' also being used for -01 in the past but
cannot now come up with solid citations.

I invented the following abbreviations in the 1990s:
+02	WAST	West Africa Summer Time
+03	CAST	Central Africa Summer Time
+03	SAST	South Africa Summer Time
+03	EAT	East Africa Time
'EAT' seems to have caught on and is in current timestamps, and though
the other abbreviations are rarer and are only in past timestamps,
they are paired with better-attested non-DST abbreviations.
Corrections are welcome.

Algeria
Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S

Attached to: Algeria (africa)

Paul Eggert (2018-09-11):

Unfortunately tzdb records only Western clock time in use in Ethiopia,
as the tzdb format is not up to properly recording a common Ethiopian
timekeeping practice that is based on solar time.  See:
Mortada D. If you have a meeting in Ethiopia, you'd better double
check the time. PRI's The World. 2015-01-30 15:15 -05.
https://www.pri.org/stories/2015-01-30/if-you-have-meeting-ethiopia-you-better-double-check-time

Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]

Attached to: Africa/Nairobi (africa)

Mohamed Essedik Najd (2018-10-26):

Today, a Moroccan government council approved the perpetual addition
of 60 minutes to the regular Moroccan timezone.

Attached to: Morocco (africa)

Matt Johnson (2018-10-28):

http://www.sgg.gov.ma/Portals/1/BO/2018/BO_6720-bis_Ar.pdf

Attached to: Morocco (africa)

Maamar Abdelkader (2018-11-01):

We usually move clocks back the previous week end and come back to the +1
the week end after....  The government does not announce yet the decision
about this temporary change.  But it s 99% sure that it will be the case,
as in previous years.  An unofficial survey was done these days, showing
that 64% of asked people are ok for moving from +1 to +0 during Ramadan.
https://leconomiste.com/article/1035870-enquete-l-economiste-sunergia-64-des-marocains-plebiscitent-le-gmt-pendant-ramadan

Attached to: Morocco (africa)

Steffen Thorsen (2018-01-08):

Multiple sources tell that São Tomé changed from UTC to UTC+1 as
they entered the year 2018.

Attached to: Africa/Sao_Tome (africa)

Michael Deckers (2018-01-08):

the switch is from 01:00 to 02:00 ... [Decree No. 25/2017]
http://www.mnec.gov.st/index.php/publicacoes/documentos/file/90-decreto-lei-n-25-2017

Attached to: Africa/Sao_Tome (africa)

Vadim Nasardinov (2018-12-29):

São Tomé and Príncipe is about to do the following on Jan 1, 2019:
https://www.stp-press.st/2018/12/05/governo-jesus-ja-decidiu-repor-hora-legal-sao-tomense/

Attached to: Africa/Sao_Tome (africa)

Michael Deckers (2018-12-30):

https://www.legis-palop.org/download.jsp?idFile=102818
... [The legal time of the country, which coincides with universal
coordinated time, will be reinstituted at 2 o'clock on day 1 of January, 2019.]

Attached to: Africa/Sao_Tome (africa)

Paul Eggert (2018-10-02):

The following comes from Table 1 of:
Li Yu. Research on the daylight saving movement in 1940s Shanghai.
Nanjing Journal of Social Sciences. 2014;(2):144-50.
http://oversea.cnki.net/kns55/detail.aspx?dbname=CJFD2014&filename=NJSH201402020
The table lists dates only; I am guessing 00:00 and 24:00 transition times.
Also, the table lists the planned end of DST in 1949, but the corresponding
zone line cuts this off on May 28, when the Communists took power.

Attached to: Shang (asia)

P Chan (2018-05-07):

The start and end time of DST in China [from 1986 on] should be 2:00
(i.e. 2:00 to 3:00 at the start and 2:00 to 1:00 at the end)....
Government notices about summer time:

1986-04-12 http://www.zj.gov.cn/attach/zfgb/198608.pdf p.21-22
(To establish summer time from 1986. On 4 May, set the clocks ahead one hour
at 2 am. On 14 September, set the clocks backward one hour at 2 am.)

1987-02-15 http://www.gov.cn/gongbao/shuju/1987/gwyb198703.pdf p.114
(Summer time in 1987 to start from 12 April until 13 September)

1987-09-09 http://www.gov.cn/gongbao/shuju/1987/gwyb198721.pdf p.709
(From 1988, summer time to start from 2 am of the first Sunday of mid-April
until 2 am of the first Sunday of mid-September)

1992-03-03 http://www.gov.cn/gongbao/shuju/1992/gwyb199205.pdf p.152
(To suspend summer time from 1992)

The first page of People's Daily on 12 April 1988 stating that summer time
to begin on 17 April.
http://data.people.com.cn/pic/101p/1988/04/1988041201.jpg

Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S

Attached to: PRC (asia)

Phake Nick (2018-10-27):

According to Singaporean newspaper
http://eresources.nlb.gov.sg/newspapers/Digitised/Article/singfreepresswk19041102-1.2.37
the day that Hong Kong start using GMT+8 should be Oct 30, 1904.

Attached to: HK (asia)

Paul Eggert (2018-11-17):

Hong Kong had a time ball near the Marine Police Station, Tsim Sha Tsui.
"The ball was raised manually each day and dropped at exactly 1pm
(except on Sundays and Government holidays)."
Dyson AD. From Time Ball to Atomic Clock. Hong Kong Government. 1983.
<https://www.hko.gov.hk/publica/gen_pub/timeball_atomic_clock.pdf>
"From 1904 October 30 the time-ball at Hong Kong has been dropped by order
of the Governor of the Colony at 17h 0m 0s G.M.T., which is 23m 18s.14 in
advance of 1h 0m 0s of Hong Kong mean time."
Hollis HP. Universal Time, Longitudes, and Geodesy. Mon Not R Astron Soc.
1905-02-10;65(4):405-6. https://doi.org/10.1093/mnras/65.4.382

Attached to: HK (asia)

Joseph Myers (2018-11-18):

An astronomer before 1925 referring to GMT would have been using the old
astronomical convention where the day started at noon, not midnight.

Attached to: HK (asia)

Steve Allen (2018-11-17):

Meteorological Observations made at the Hongkong Observatory in the year 1904
page 4 <https://books.google.com/books?id=kgw5AQAAMAAJ&pg=RA4-PA4>
... the log of drop times in Table II shows that on Sunday 1904-10-30 the
ball was dropped.  So that looks like a special case drop for the sake
of broadcasting the new local time.

Attached to: HK (asia)

Phake Nick (2018-11-18):

According to The Hong Kong Weekly Press, 1904-10-29, p.324, the
governor of Hong Kong at the time stated that "We are further desired to
make it known that the change will be effected by firing the gun and by the
dropping of the Ball at 23min. 18sec. before one."

Attached to: HK (asia)

Paul Eggert (2018-11-18):

See <https://mmis.hkpl.gov.hk> for this; unfortunately Flash is required.

Attached to: HK (asia)

Phake Nick (2018-10-26):

I went to check microfilm records stored at Hong Kong Public Library....
on September 30 1941, according to Ta Kung Pao (Hong Kong edition), it was
stated that fallback would occur on the next day (the 1st)'s "03:00 am (Hong
Kong Time 04:00 am)" and the clock will fall back for a half hour. (03:00
probably refer to the time commonly used in mainland China at the time given
the paper's background) ... the sunrise/sunset time given by South China
Morning Post for October 1st was indeed moved by half an hour compares to
before.  After that, in December, the battle to capture Hong Kong started and
the library doesn't seems to have any record stored about press during that
period of time.  Some media resumed publication soon after that within the
same month, but there were not much information about time there.  Later they
started including a radio program guide when they restored radio service,
explicitly mentioning it use Tokyo standard time, and later added a note
saying it's half an hour ahead of the old Hong Kong standard time, and it
also seems to indicate that Hong Kong was not using GMT+8 when it was
captured by Japan.

Image of related sections on newspaper:
* 1941-09-30, Ta Kung Pao (Hong Kong), "Winter Time start tomorrow".
https://i.imgur.com/6waY51Z.jpg (Chinese)
* 1941-09-29, South China Morning Post, Information on sunrise/sunset
time and other things for September 30 and October 1.
https://i.imgur.com/kCiUR78.jpg
* 1942-02-05. The Hong Kong News, Radio Program Guide.
https://i.imgur.com/eVvDMzS.jpg
* 1941-06-14. Hong Kong Daily Press, Daylight Saving from 3am Tomorrow.
https://i.imgur.com/05KkvtC.png
* 1941-09-30, Hong Kong Daily Press, Winter Time Warning.
https://i.imgur.com/dge4kFJ.png

Attached to: HK (asia)

P Chan (2018-12-31):

* According to the Hong Kong Daylight-Saving Regulations, 1941, the
1941 spring-forward transition was at 03:00.
http://sunzi.lib.hku.hk/hkgro/view/g1941/304271.pdf
http://sunzi.lib.hku.hk/hkgro/view/g1941/305516.pdf
* According to some articles from South China Morning Post, +08 was
resumed on 1945-11-18 at 02:00.
https://i.imgur.com/M2IsZ3c.png
https://i.imgur.com/iOPqrVo.png
https://i.imgur.com/fffcGDs.png
* Some newspapers ... said the 1946 spring-forward transition was on
04-21 at 00:00.  The Kung Sheung Evening News 1946-04-20 (Chinese)
https://i.imgur.com/ZSzent0.png
https://mmis.hkpl.gov.hk///c/portal/cover?c=QF757YsWv5%2FH7zGe%2FKF%2BFLYsuqGhRBfe p.4
The Kung Sheung Daily News 1946-04-21 (Chinese)
https://i.imgur.com/7ecmRlcm.png
https://mmis.hkpl.gov.hk///c/portal/cover?c=QF757YsWv5%2BQBGt1%2BwUj5qG2GqtwR3Wh p.4
* According to the Summer Time Ordinance (1946), the fallback
transitions between 1946 and 1952 were at 03:30 Standard Time (+08)
http://oelawhk.lib.hku.hk/archive/files/bb74b06a74d5294620a15de560ab33c6.pdf
* Some other laws and regulations related to DST from 1953 to 1979
Summer Time Ordinance 1953
https://i.imgur.com/IOlJMav.jpg
Summer Time (Amendment) Ordinance 1965
https://i.imgur.com/8rofeLa.jpg
Interpretation and General Clauses Ordinance (1966)
https://i.imgur.com/joy3msj.jpg
Emergency (Summer Time) Regulation 1973 <https://i.imgur.com/OpRWrKz.jpg>
Interpretation and General Clauses (Amendment) Ordinance 1977
https://i.imgur.com/RaNqnc4.jpg
Resolution of the Legislative Council passed on 9 May 1979
https://www.legco.gov.hk/yr78-79/english/lc_sitg/hansard/h790509.pdf#page=39

Attached to: HK (asia)

P Chan (2018-05-10):

* LegisMac
http://legismac.safp.gov.mo/legismac/descqry/Descqry.jsf?lang=pt
A database for searching titles of legal documents of Macau in
Chinese and Portuguese.  The term "HORÁRIO DE VERÃO" can be used for
searching decrees about summer time.
* Archives of Macao
http://www.archives.gov.mo/en/bo/
It contains images of old official gazettes.
* The Macao Meteorological and Geophysical Bureau have a page listing the
summer time history.  But it is not complete and has some mistakes.
http://www.smg.gov.mo/smg/geophysics/e_t_Summer%20Time.htm
Macau adopted GMT+8 on 30 Oct 1904 to follow Hong Kong.  Clocks were
advanced by 25 minutes and 50 seconds.  Which means the LMT used was
+7:34:10.  As stated in the "Portaria No. 204" dated 21 October 1904
and published in the Official Gazette on 29 October 1904.
http://igallery.icm.gov.mo/Images/Archives/BO/MO_AH_PUB_BO_1904_10/MO_AH_PUB_BO_1904_10_00025_Grey.JPG

Therefore the 1911 decree of Portugal did not change time in Macau.

From LegisMac, here is a list of decrees that changed the time ...
[Decree Gazette-no. date; titles omitted in this quotation]
DIL 732 BOCM 51 1941.12.20
DIL 764 BOCM 9S 1942.04.30
DIL 781 BOCM 21 1942.10.10
PT 3434 BOCM 8S 1943.04.17
PT 3504 BOCM 20 1943.09.25
PT 3843 BOCM 39 1945.09.29
PT 3961 BOCM 17 1946.04.27
PT 4026 BOCM 39 1946.09.28
PT 4153 BOCM 16 1947.04.10
PT 4271 BOCM 48 1947.11.29
PT 4374 BOCM 18 1948.05.01
PT 4465 BOCM 44 1948.10.30
PT 4590 BOCM 14 1949.04.02
PT 4666 BOCM 44 1949.10.29
PT 4771 BOCM 12 1950.03.25
PT 4838 BOCM 43 1950.10.28
PT 4946 BOCM 12 1951.03.24
PT 5025 BO 43 1951.10.27
PT 5149 BO 14 1952.04.05
PT 5251 BO 43 1952.10.25
PT 5366 BO 13 1953.03.28
PT 5444 BO 44 1953.10.31
PT 5540 BO 12 1954.03.20
PT 5589 BO 44 1954.10.30
PT 5676 BO 12 1955.03.19
PT 5739 BO 45 1955.11.05
PT 5823 BO 11 1956.03.17
PT 5891 BO 44 1956.11.03
PT 5981 BO 12 1957.03.23
PT 6064 BO 43 1957.10.26
PT 6172 BO 12 1958.03.22
PT 6243 BO 43 1958.10.25
PT 6341 BO 12 1959.03.21
PT 6411 BO 43 1959.10.24
PT 6514 BO 11 1960.03.12
PT 6584 BO 44 1960.10.29
PT 6721 BO 10 1961.03.11
PT 6815 BO 43 1961.10.28
PT 6947 BO 10 1962.03.10
PT 7080 BO 43 1962.10.27
PT 7218 BO 12 1963.03.23
PT 7340 BO 43 1963.10.26
PT 7491 BO 11 1964.03.14
PT 7664 BO 43 1964.10.24
PT 7846 BO 15 1965.04.10
PT 7979 BO 42 1965.10.16
PT 8146 BO 15 1966.04.09
PT 8252 BO 41 1966.10.08
PT 8429 BO 15 1967.04.15
PT 8540 BO 41 1967.10.14
PT 8735 BO 15 1968.04.13
PT 8860 BO 41 1968.10.12
PT 9035 BO 16 1969.04.19
PT 9156 BO 42 1969.10.18
PT 9328 BO 15 1970.04.11
PT 9418 BO 41 1970.10.10
PT 9587 BO 14 1971.04.03
PT 9702 BO 41 1971.10.09
PT 38-A/72 BO 14 1972.04.01
PT 126-A/72 BO 41 1972.10.07
PT 61/73 BO 14 1973.04.07
PT 182/73 BO 40 1973.10.06
PT 282/73 BO 51 1973.12.22
PT 177/74 BO 41 1974.10.12
PT 51/75 BO 15 1975.04.12
PT 173/75 BO 41 1975.10.11
PT 67/76/M BO 14 1976.04.03
PT 169/76/M BO 41 1976.10.09
PT 78/79/M BO 19 1979.05.12
PT 166/79/M BO 42 1979.10.20
Note that DIL 732 does not belong to "HORÁRIO DE VERÃO" according to
LegisMac.... Note that between 1942 and 1945, the time switched
between GMT+9 and GMT+10.  Also in 1965 and 1965 the DST ended at 2:30am.

Attached to: Macau (asia)

Paul Eggert (2018-05-10):

The 1904 decree says that Macau changed from the meridian of
Fortaleza do Monte, presumably the basis for the 7:34:10 for LMT.

Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S

Attached to: Macau (asia)

Takayuki Nikai (2018-01-19):

The source of information is Japanese law.
http://www.shugiin.go.jp/internet/itdb_housei.nsf/html/houritsu/00219480428029.htm
http://www.shugiin.go.jp/internet/itdb_housei.nsf/html/houritsu/00719500331039.htm
... In summary, it is written as follows.  From 24:00 on the first Saturday
in May, until 0:00 on the day after the second Saturday in September.

Attached to: Japan (asia)

Phake Nick (2018-09-27):

[T]he webpage authored by National Astronomical Observatory of Japan
https://eco.mtk.nao.ac.jp/koyomi/wiki/BBFEB9EF2FB2C6BBFEB9EF.html
... mentioned that using Showa 23 (year 1948) as example, 13pm of September
11 in summer time will equal to 0am of September 12 in standard time.
It cited a document issued by the Liaison Office which briefly existed
during the postwar period of Japan, where the detail on implementation
of the summer time is described in the document.
https://eco.mtk.nao.ac.jp/koyomi/wiki/BBFEB9EF2FB2C6BBFEB9EFB2C6BBFEB9EFA4CEBCC2BBDCA4CBA4C4A4A4A4C6.pdf
The text in the document do instruct a fall back to occur at
September 11, 13pm in summer time, while ordinary citizens can
change the clock before they sleep.

Attached to: Japan (asia)

Paul Eggert (2018-09-27):

This instruction is equivalent to "Sat>=8 25:00", so use that.  zic treats
it like "Sun>=9 01:00", which is not quite the same but is the best we can
do in any POSIX or C platform.  The "25:00" assumes zic from 2007 or later,
which should be safe now.

Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S

Attached to: Japan (asia)

Alexander Konzurovski (2018-12-20):

(Asia/Qyzylorda) is changing its time zone from UTC+6 to UTC+5
effective December 21st, 2018....
http://adilet.zan.kz/rus/docs/P1800000817 (russian language).

Attached to: Asia/Almaty (asia)

Phake Nick (2018-10-27):

1. According to official announcement from Korean government, the DST end
date in South Korea should be
1955-09-08 without specifying time
http://theme.archives.go.kr/next/common/viewEbook.do?singleData=N&archiveEventId=0027977557
1956-09-29 without specifying time
http://theme.archives.go.kr/next/common/viewEbook.do?singleData=N&archiveEventId=0027978341
1957-09-21 24 o'clock
http://theme.archives.go.kr/next/common/viewEbook.do?singleData=N&archiveEventId=0027979690#3
1958-09-20 24 o'clock
http://theme.archives.go.kr/next/common/viewEbook.do?singleData=N&archiveEventId=0027981189
1959-09-19 24 o'clock
http://theme.archives.go.kr/next/common/viewEbook.do?singleData=N&archiveEventId=0027982974#2
1960-09-17 24 o'clock
http://theme.archives.go.kr/next/common/viewEbook.do?singleData=N&archiveEventId=0028044104
...
2.... https://namu.wiki/w/대한민국%20표준시 ... [says]
when Korea was using GMT+8:30 as standard time, the international
aviation/marine/meteorological industry in the country refused to
follow and continued to use GMT+9:00 for interoperability.


Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S

Attached to: ROK (asia)

Kang Seonghoon (2018-04-29):

North Korea will revert its time zone from UTC+8:30 (PYT; Pyongyang
Time) back to UTC+9 (KST; Korea Standard Time).

Attached to: Asia/Seoul (asia)

Seo Sanghyeon (2018-04-30):

Rodong Sinmun 2018-04-30 announced Pyongyang Time transition plan.
https://www.nknews.org/kcna/wp-content/uploads/sites/5/2018/04/rodong-2018-04-30.pdf
... the transition date is 2018-05-05 ...  Citation should be Decree
No. 2232 of April 30, 2018, of the Presidium of the Supreme People's
Assembly, as published in Rodong Sinmun.

Attached to: Asia/Seoul (asia)

Tim Parenti (2018-04-29):

It appears to be the front page story at the top in the right-most column.

Attached to: Asia/Seoul (asia)

Paul Eggert (2018-05-04):

The BBC reported that the transition was from 23:30 to 24:00 today.
https://www.bbc.com/news/world-asia-44010705

Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]

Attached to: Asia/Seoul (asia)

Sharef Mustafa (2018-03-16):

Palestine summer time will start on Mar 24th 2018 ...
http://www.palestinecabinet.gov.ps/Website/AR/NDecrees/ViewFile.ashx?ID=e7a42ab7-ee23-435a-b9c8-a4f7e81f3817

Attached to: EgyptAsia (asia)

Paul Eggert (2018-06-19):

I surveyed recent news reports, and my impression is that "PST" is
more popular among reliable English-language news sources.  This is
not just a measure of Google hit counts: it's also the sizes and
influence of the sources.  There is no current abbreviation for DST,
so use "PDT", the usual American style.

Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S

Attached to: Phil (asia)

Paul Eggert (2018-08-29):

Time in Saudi Arabia and other countries in the Arabian peninsula was not
standardized until 1968 or so; we don't know exactly when, and possibly it
has never been made official.  Richard P Hunt, in "Islam city yielding to
modern times", New York Times (1961-04-09), p 20, wrote that only airlines
observed standard time, and that people in Jeddah mostly observed quasi-solar
time, doing so by setting their watches at sunrise to 6 o'clock (or to 12
o'clock for "Arab" time).

Timekeeping differed depending on who you were and which part of Saudi
Arabia you were in.  In 1969, Elias Antar wrote that although a common
practice had been to set one's watch to 12:00 (i.e., midnight) at sunset -
which meant that the time on one side of a mountain could differ greatly from
the time on the other side - many foreigners set their watches to 6pm
instead, while airlines instead used UTC +03 (except in Dhahran, where they
used UTC +04), Aramco used UTC +03 with DST, and the Trans-Arabian Pipe Line
Company used Aramco time in eastern Saudi Arabia and airline time in western.
(The American Military Aid Advisory Group used plain UTC.)  Antar writes,
"A man named Higgins, so the story goes, used to run a local power
station. One day, the whole thing became too much for Higgins and he
assembled his staff and laid down the law. 'I've had enough of this,' he
shrieked. 'It is now 12 o'clock Higgins Time, and from now on this station is
going to run on Higgins Time.' And so, until last year, it did."  See:
Antar E. Dinner at When? Saudi Aramco World, 1969 March/April. 2-3.
http://archive.aramcoworld.com/issue/196902/dinner.at.when.htm
Also see: Antar EN. Arabian flying is confusing.
Port Angeles (WA) Evening News. 1965-03-10. page 3.

The TZ database cannot represent quasi-solar time; airline time is the best
we can do.  The 1946 foreign air news digest of the U.S. Civil Aeronautics
Board (OCLC 42299995) reported that the "... Arabian Government, inaugurated
a weekly Dhahran-Cairo service, via the Saudi Arabian cities of Riyadh and
Jidda, on March 14, 1947".  Shanks & Pottenger guessed 1950; go with the
earlier date.

Shanks & Pottenger also state that until 1968-05-01 Saudi Arabia had two
time zones; the other zone, at UT +04, was in the far eastern part of
the country.  Presumably this is documenting airline time.  Ignore this,
as it's before our 1970 cutoff.

Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]

Attached to: Asia/Riyadh (asia)

Raymond Kumar (2018-07-13):

http://www.fijitimes.com/government-approves-2018-daylight-saving/
... The daylight saving period will end at 3am on Sunday January 13, 2019.

Attached to: Fiji (australasia)

Paul Eggert (2018-11-18):

Unless otherwise specified, the source for data through 1990 is:
Thomas G. Shanks and Rique Pottenger, The International Atlas (6th edition),
San Diego: ACS Publications, Inc. (2003).
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 (IATA SSIM),
published semiannually.  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.

Another source occasionally used is Edward W. Whitman, World Time Differences,
Whitman Publishing Co, 2 Niagara Av, Ealing, London (undated), which
I found in the UCLA library.

For data circa 1899, a common source is:
Milne J. Civil time. Geogr J. 1899 Feb;13(2):173-94.
https://www.jstor.org/stable/1774359

For the 1911/1912 establishment of standard time in French possessions, see:
Société Française de Physique, Recueil de constantes physiques (1913),
page 752, 18b.

A reliable and entertaining source about time zones is
Derek Howse, Greenwich time and longitude, Philip Wilson Publishers (1997).

I invented the abbreviation marked "*".
The following abbreviations are from other sources.
Corrections are welcome!
std	dst
LMT		Local Mean Time
8:00	AWST	AWDT	Western Australia
9:30	ACST	ACDT	Central Australia
10:00	AEST	AEDT	Eastern Australia
10:00	GST	GDT*	Guam through 2000
10:00	ChST		Chamorro
11:30	NZMT	NZST	New Zealand through 1945
12:00	NZST	NZDT	New Zealand 1946-present
-11:00	SST		Samoa
-10:00	HST		Hawaii

See the 'northamerica' file for Hawaii.
See the 'southamerica' file for Easter I and the Galápagos Is.

Paul Eggert (2018-04-01):

The Guardian Express of Perth, Australia reported today that the
government decided to advance the clocks permanently on January 1,
2019, from UT +08 to UT +09.  The article noted that an exemption
would be made for people aged 61 and over, who "can apply in writing
to have the extra hour of sunshine removed from their area."  See:
Daylight saving coming to WA in 2019. Guardian Express. 2018-04-01.
https://www.communitynews.com.au/guardian-express/news/exclusive-daylight-savings-coming-wa-summer-2018/
[The article ends with "Today's date is April 1."]

The Australian Bureau of Meteorology FAQ
http://www.bom.gov.au/faq/faqgen.htm
(1999-09-27) writes that Giles Meteorological Station uses
South Australian time even though it's located in Western Australia.

Paul Eggert (2018-02-26):

I lack access to the following source for Queensland DST:
Pearce C. History of daylight saving time in Queensland.
Queensland Hist J. 2017 Aug;23(6):389-403
https://search.informit.com.au/documentSummary;dn=994682348436426;res=IELHSS

Kerry Shetline (2018-02-03):

December 31 was the day that was skipped, so that the transition
would be from Friday December 30, 1994 to Sunday January 1, 1995.

Paul Eggert (2018-02-04):

One source for this is page 202 of: Bartky IR. One Time Fits All:
The Campaigns for Global Uniformity (2007).

Kanton

Phake Nick (2018-10-27):

Guam Island was briefly annexed by Japan during ... year 1941-1944 ...
however there are no detailed information about what time it use during that
period.  It would probably be reasonable to assume Guam use GMT+9 during
that period of time like the surrounding area.

Paul Eggert (2018-11-18):

Like the Ladrones (see Guam commentary), assume the Spanish East Indies
kept American time until the Philippines switched at the end of 1844.

Phake Nick (2018-10-27):

From a Japanese wiki site https://wiki.suikawiki.org/n/南洋群島の標準時
...
For "Southern Islands" (modern region of Mariana + Palau + Federation of
Micronesia + Marshall Islands):

A 1906 Japanese magazine shown the Caroline Islands and Mariana Islands
who was occupied by Germany at the time as GMT+10, together with the like
of German New Guinea.  However there is a marking saying it have not been
implemented (yet).  No further information after that were found.

Japan invaded those islands in 1914, and records shows that they were
instructed to use JST at the time.

1915 January telecommunication record on the Jaluit Atoll shows they use
the meridian of 170E as standard time (GMT+11:20), which is similar to the
longitude of the atoll.
1915 February record say the 170E standard time is to be used until
February 9 noon, and after February 9 noon they are to use JST.
However these are time used within the Japanese Military at the time and
probably does not reflect the time used by local resident at the time (that
is if they keep their own time back then)

In January 1919 the occupying force issued a command that split the area
into three different timezone with meridian of 135E, 150E, 165E (JST+0, +1,
+2), and the command was to become effective from February 1 of the same
year.  Despite the target of the command is still only for the occupying
force itself, further publication have described the time as the standard
time for the occupied area and thus it can probably be seen as such.
* Area that use meridian of 135E: Palau and Yap civil administration area
(Southern Islands Western Standard Time)
* Area that use meridian of 150E: Truk (Chuuk) and Saipan civil
administration area (Southern Islands Central Standard Time)
* Area that use meridian of 165E: Ponape (Pohnpei) and Jaluit civil
administration area (Southern Islands Eastern Standard Time).
* In the next few years Japanese occupation of those islands have been
formalized via League of Nation Mandate (South Pacific Mandate) and formal
governance structure have been established, these district [become
subprefectures] and timezone classification have been inherited as standard
time of the area.
* Saipan subprefecture include Mariana islands (exclude Guam which was
occupied by America at the time), Palau and Yap subprefecture rule the
Western Caroline Islands with 137E longitude as border, Truk and Ponape
subprefecture rule the Eastern Caroline Islands with 154E as border, Ponape
subprefecture also rule part of Marshall Islands to the west of 164E
starting from (1918?) and Jaluit subprefecture rule the rest of the
Marshall Islands.

And then in year 1937, an announcement was made to change the time in the
area into 2 timezones:
* Area that use meridian of 135E: area administered by Palau, Yap and
Saipan subprefecture (Southern Islands Western Standard Time)
* Area that use meridian of 150E: area administered by Truk (Chuuk),
Ponape (Pohnpei) and Jaluit subprefecture (Southern Islands Eastern
Standard Time)

Another announcement issued in 1941 say that on April 1 that year,
standard time of the Southern Islands would be changed to use the meridian
of 135E (GMT+9), and thus abolishing timezone different within the area.

Then Pacific theater of WWII started and Japan slowly lose control on the
island.  The webpage I linked above contain no information during this
period of time....

After the end of WWII, in 1946 February, a document written by the
(former?) Japanese military personnel describe there are 3 hours time
different between Caroline islands time/Wake island time and the Chungking
time, which would mean the time being used there at the time was GMT+10.

After that, the area become Trust Territories of the Pacific Islands
under American administration from year 1947.  The site listed some
American/International books/maps/publications about time used in those
area during this period of time but they doesn't seems to be reliable
information so it would be the best if someone know where can more reliable
information can be found.

Paul Eggert (2018-11-18):

For the above, use vague dates like "1914" and "1945" for transitions that
plausibly exist but for which the details are not known.  The information
for Wake is too sketchy to act on.

The 1906 GMT+10 info about German-controlled islands might not have been
done, so omit it from the data for now.

The Jaluit info governs Kwajalein.


Midway

From Charles T O'Connor, KMTH DJ (1956),
quoted in the KTMH section of the Radio Heritage Collection
<http://radiodx.com/spdxr/KMTH.htm> (2002-12-31):
For the past two months we've been on what is known as Daylight
Saving Time.  This time has put us on air at 5am in the morning,
your time down there in New Zealand.  Starting September 2, 1956
we'll again go back to Standard Time.  This'll mean that we'll go to
air at 6am your time.

Phake Nick (2018-10-31):

Currently, the tz database say Nauru use LMT until 1921, and then
switched to GMT+11:30 for the next two decades.
However, a number of timezone map published in America/Japan back then
showed its timezone as GMT+11 per https://wiki.suikawiki.org/n/ナウルの標準時
And it would also be nice if the 1921 transition date could be sourced.
...
The "Nauru Standard Time Act 1978 Time Change"
http://ronlaw.gov.nr/nauru_lpms/files/gazettes/4b23a17d2030150404db7a5fa5872f52.pdf#page=3
based on "Nauru Standard Time Act 1978 Time Change"
http://www.paclii.org/nr/legis/num_act/nsta1978207/ defined that "Nauru
Alternative Time" (GMT+12) should be in effect from 1979 Feb.

Paul Eggert (2018-11-19):

The 1921-01-15 introduction of standard time is in Shanks; it is also in
"Standard Time Throughout the World", US National Bureau of Standards (1935),
https://nvlpubs.nist.gov/nistpubs/Legacy/circ/nbscircular406.pdf
page 3, which does not give the UT offset.  In response to a comment by
Phake Nick I set the Nauru time of occupation by Japan to
1942-08-29/1945-09-08 by using dates from:
https://en.wikipedia.org/wiki/Japanese_occupation_of_Nauru

Norfolk

Paul Eggert (2018-02-15):

In January 2018 we discovered that the negative SAVE values in the
Eire rules cause problems with tests for ICU:
https://mm.icann.org/pipermail/tz/2018-January/025825.html
and with tests for OpenJDK:
https://mm.icann.org/pipermail/tz/2018-January/025822.html

To work around this problem, the build procedure can translate the
following data into two forms, one with negative SAVE values and the
other form with a traditional approximation for Irish timestamps
after 1971-10-31 02:00 UTC; although this approximation has tm_isdst
flags that are reversed, its UTC offsets are correct and this often
suffices....

The following is like GB-Eire and EU, except with standard time in
summer and negative daylight saving time in winter.  It is for when
negative SAVE values are used.
Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S

Attached to: Eire (europe)

Michael Deckers (2018-02-15):

article 5 [of the 1911 decree; Deckers's translation] ...:
These dispositions shall enter into force at the instant at which,
according to the 2nd article, the civil day January 1, 1912 begins,
all clocks therefore having to be advanced or set back correspondingly ...

Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S

Attached to: Port (europe)

Marat Nigametzianov (2018-07-16):

this is link to order from 1956 about timezone in USSR
http://astro.uni-altai.ru/~orion/blog/2011/11/novyie-granitsyi-chasovyih-poyasov-v-sssr/

Attached to: Europe/Kaliningrad (europe)

Paul Eggert (2018-07-16):

Perhaps someone could translate the link mentioned above, and use it
to correct our data for the ex-Soviet Union.  It cites the following:
«Поясное время и новые границы часовых поясов» / сост. П.Н. Долгов,
отв. ред. Г.Д. Бурдун - М: Комитет стандартов, мер и измерительных
приборов при Совете Министров СССР, Междуведомственная комиссия
единой службы времени, 1956 г.
This book looks like it would be a helpful resource for the Soviet
Union through 1956.  Although a copy was in the Scientific Library
of Tomsk State University, I have not been able to track down a copy nearby.

Attached to: Europe/Kaliningrad (europe)

Stepan Golosunov (2018-07-21):

http://astro.uni-altai.ru/~orion/blog/2015/05/center-reforma-ischisleniya-vremeni-br-na-territorii-sssr-v-1957-godu-center/
says that the 1956 decision to change time belts' borders was not
implemented as planned in 1956 and the change happened in 1957.
There is also the problem that actual time zones were different from
the official time belts (and from many time belts' maps) as there were
numerous exceptions to application of time belt rules.  For example,
https://ru.wikipedia.org/wiki/Московское_время#Перемещение_границы_применения_московского_времени_на_восток
says that by 1962 there were many regions in the 3rd time belt that
were on Moscow time, referring to a 1962 map.  By 1989 number of such
exceptions grew considerably.

Attached to: Europe/Kaliningrad (europe)

Alexander Fetisov (2018-09-20):

Volgograd region in southern Russia (Europe/Volgograd) change
timezone from UTC+3 to UTC+4 from 28oct2018.
http://sozd.parliament.gov.ru/bill/452878-7

Attached to: Europe/Volgograd (europe)

Stepan Golosunov (2018-10-11):

The law has been published today on
http://publication.pravo.gov.ru/Document/View/0001201810110037

Attached to: Europe/Volgograd (europe)

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....

Attached to: Chicago (northamerica)

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	-	IN	ON	AT	SAVE	LETTER

Attached to: Denver (northamerica)

Ryan Stanley (2018-11-06):

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.
https://www.facebook.com/141055983004923/photos/pb.141055983004923.-2207520000.1541465673./569081370202380/

Attached to: America/Juneau (northamerica)

Paul Eggert (2018-12-16):

In a 2018-12-11 special election, Metlakatla voted to go back to
Alaska time (including daylight saving time) starting next year.
https://www.krbd.org/2018/12/12/metlakatla-to-follow-alaska-standard-time-allow-liquor-sales/

Attached to: America/Juneau (northamerica)

Paul Eggert (2018-11-30):

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."
How Indiana went from 'God's time' to split zones and daylight-saving.
Indianapolis Star. 2018-11-27 14:58 -05.
https://www.indystar.com/story/news/politics/2018/11/27/indianapolis-indiana-time-zone-history-central-eastern-daylight-savings-time/2126300002/

Attached to: Indianapolis (northamerica)

Paul Eggert (2018-03-20):

The Louisville & Nashville Railroad's 1883-11-18 change occurred at
10:00 old local time; train were supposed to come to a standstill
for precisely 18 minutes.  See Bartky Fig. 1 (page 50).  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.

Attached to: Louisville (northamerica)

Paul Eggert (2018-01-31):

Hora de verano para la República Argentina
http://buenasiembra.com.ar/esoterismo/astrologia/hora-de-verano-de-la-republica-argentina-27.html
says that standard time in Argentina from 1894-10-31
to 1920-05-01 was -4:16:48.25.  Go with this more precise value
over Shanks & Pottenger.  It is upward compatible with Milne, who
says Córdoba time was -4:16:48.2.

Attached to: America/Argentina/Buenos_Aires (southamerica)

Paul Eggert (2018-01-23):

Perhaps San Luis operates on the legal fiction that it is at -04
with perpetual daylight saving time, but ordinary usage typically seems to
just say it's at -03; see, for example,
https://es.wikipedia.org/wiki/Hora_oficial_argentina
We've documented similar situations as being plain changes to
standard time, so let's do that here too.  This does not change UTC
offsets, only tm_isdst and the time zone abbreviations.  One minor
plus is that this silences a zic complaint that there's no POSIX TZ
setting for timestamps past 2038.

Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]

Buenos Aires (BA), Capital Federal (CF),

Attached to: America/Argentina/Buenos_Aires (southamerica)

Fábio Gomes (2018-10-04):

The Brazilian president just announced a new change on this year DST.
It was scheduled to start on November 4th and it was changed to November 18th.

Attached to: Brazil (southamerica)

Rodrigo Brüning Wessler (2018-10-15):

The Brazilian government just announced that the change in DST was
canceled....  Maybe the president Michel Temer also woke up one hour
earlier today. :)

Attached to: Brazil (southamerica)

Juan Correa (2018-08-13):

As of moments ago, the Ministry of Energy in Chile has announced the new
schema for DST. ...  Announcement in video (in Spanish):
https://twitter.com/MinEnergia/status/1029000399129374720

Attached to: Chile (southamerica)

Yonathan Dossow (2018-08-13):

The video says "first Saturday of September", we all know it means Sunday at
midnight.

Attached to: Chile (southamerica)

Tim Parenti (2018-08-13):

Translating the captions on the video at 0:44-0:55, "We want to announce as
Government that from 2019, Winter Time will be increased to 5 months, between
the first Saturday of April and the first Saturday of September."
At 2:08-2:20, "The Magallanes region will maintain its current time, as
decided by the citizens during 2017, but our Government will promote a
regional dialogue table to gather their opinion on this matter."
https://twitter.com/MinEnergia/status/1029009354001973248
"We will keep the new time policy unchanged for at least the next 4 years."
So we extend the new rules on Saturdays at 24:00 mainland time indefinitely.

Attached to: Chile (southamerica)

Tim Parenti (2018-02-15):

http://www.impo.com.uy/diariooficial/1933/10/27/6

It appears Ley No. 9122 of 1933 was never published as such in the Diario
Oficial, but instead appeared as Document 26 in the Diario on Friday
1933-10-27 as a decree made Monday 1933-10-23 and filed under the Ministry of
National Defense.  It reinstituted a DST of 30 minutes (to UT-03) "from the
last Sunday of October...until the last Saturday of March."  In accordance
with this provision, the first transition was explicitly specified in Article
2 of the decree as Saturday 1933-10-28 at 24:00; that is, Sunday 1933-10-29
at 00:00.  Assume transitions at 00:00 Sunday throughout.

Departing from the matter-of-fact nature of previous timekeeping laws, the
1933 decree "consider[s] the advantages of...the advance of legal time":

"Whereas: The measure adopted by almost all nations at the time of the last
World War still persists in North America and Europe, precisely because of
the economic, hygienic, and social advantages derived from such an
emergency measure...

Whereas: The advance of the legal time during the summer seasons, by
displacing social activity near sunrise, favors the citizen populations
and especially the society that creates and works..."

It further specified that "necessary measures" be taken to ensure that
"public spectacles finish, in general, before [01:00]."

Attached to: Uruguay (southamerica)

Tim Parenti (2018-02-15):

Most of the Rules below, and their contemporaneous Zone lines, have been
updated simply to match the Almanaque 2018.  Although the document does not
list exact transition times, midnight transitions were already present in our
data here for all transitions through 2004-09, and this is both consistent
with prior transitions and verified in several decrees marked below between
1939-09 and 2004-09, wherein the relevant text was typically of the form:

"From 0 hours on [date], the legal time of the entire Republic will be...

In accordance with [the preceding], on [previous date] at 24 hours, all
clocks throughout the Republic will be [advanced/retarded] by..."

It is possible that there is greater specificity to be found for the Rules
below, but it is buried in no fewer than 40 different decrees individually
referenced by the Almanaque for the period from 1939-09 to 2014-09.
Four-fifths of these were promulgated less than two weeks before taking
effect; more than half within a week and none more than 5 weeks.  Only the
handful with comments below have been checked with any thoroughness.

Attached to: Uruguay (southamerica)

Tim Parenti (2018-02-15):

Decreto 1145 of the Ministry of National Defense, dated 1941-07-26, specified
UT-03 from Friday 1941-08-01 00:00, citing an "urgent...need to save fuel".
http://www.impo.com.uy/diariooficial/1941/08/04/1

Attached to: Uruguay (southamerica)

Tim Parenti (2018-02-15):

Decreto 1866 of the Ministry of National Defense, dated 1942-12-09, specified
further advancement (to UT-02:30) from Sunday 1942-12-13 24:00.  Since clocks
never went back to UT-03:30 thereafter, this is modeled as advancing standard
time by 30 minutes to UT-03, while retaining 30 minutes of DST.
http://www.impo.com.uy/diariooficial/1942/12/16/3

Attached to: Uruguay (southamerica)

Tim Parenti (2018-02-15):

Decreto 321/968 of 1968-05-25, citing emergency drought measures decreed the
day before, brought clocks forward 30 minutes from Monday 1968-05-27 00:00.
http://www.impo.com.uy/diariooficial/1968/05/30/5

Attached to: Uruguay (southamerica)

Tim Parenti (2018-02-15):

Decreto 188/970 of 1970-04-23 instituted restrictions on electricity
consumption "as a consequence of the current rainfall regime in the country".
Articles 13 and 14 advanced clocks by an hour from Saturday 1970-04-25 00:00.
http://www.impo.com.uy/diariooficial/1970/04/29/4

Attached to: Uruguay (southamerica)

Tim Parenti (2018-02-15):

Decreto 29/974 of 1974-01-11, citing "the international rise in the price of
oil", advanced clocks by 90 minutes (to UT-01:30).  Decreto 163/974 of
1974-03-04 returned 60 of those minutes (to UT-02:30), and the remaining 30
minutes followed in Decreto 679/974 of 1974-08-29.
http://www.impo.com.uy/diariooficial/1974/01/22/11
http://www.impo.com.uy/diariooficial/1974/03/14/3
http://www.impo.com.uy/diariooficial/1974/09/04/6

Attached to: Uruguay (southamerica)

Tim Parenti (2018-02-15):

Decreto 725/987 of 1987-12-04 cited "better use of national tourist
attractions" to advance clocks one hour from Monday 1987-12-14 00:00.
http://www.impo.com.uy/diariooficial/1988/01/25/1

Attached to: Uruguay (southamerica)

Tim Parenti (2018-02-15):

IATA agrees as below for 1990-10 through 1993-02.  Per Almanaque 2018, the
1992/1993 season appears to be the first in over half a century where DST
both began and ended pursuant to the same decree.

Attached to: Uruguay (southamerica)

Tim Parenti (2018-02-15):

Decreto 328/004 of 2004-09-15.
http://www.impo.com.uy/diariooficial/2004/09/23/documentos.pdf#page=1

Attached to: Uruguay (southamerica)

Tim Parenti (2018-02-15):

This 2005 postponement is not in Almanaque 2018.  Go with the contemporaneous
reporting, which is confirmed by Decreto 107/005 of 2005-03-10 amending
Decreto 328/004:
http://www.impo.com.uy/diariooficial/2005/03/15/documentos.pdf#page=1
The original decree specified a transition of 2005-03-12 24:00, but the new
one specified 2005-03-27 02:00.

Attached to: Uruguay (southamerica)

Tim Parenti (2018-02-15):

Decreto 318/005 of 2005-09-19.
http://www.impo.com.uy/diariooficial/2005/09/23/documentos.pdf#page=1

Attached to: Uruguay (southamerica)

Tim Parenti (2018-02-15):

Decreto 311/006 of 2006-09-04 established regular DST from the first Sunday
of October at 02:00 through the second Sunday of March at 02:00.  Almanaque
2018 appears to have a few typoed dates through this period; ignore them.
http://www.impo.com.uy/diariooficial/2006/09/08/documentos.pdf#page=1

Attached to: Uruguay (southamerica)

Tim Parenti (2018-02-15):

Decreto 178/015 of 2015-06-29; repeals Decreto 311/006.

This Zone can be simplified once we assume zic %z.

Attached to: America/Montevideo (southamerica)

Paul Eggert (2018-03-18):

America/Chillicothe would be tricky, as it was a city of two-timers:
"To prevent a constant mixup at Chillicothe, caused by the courthouse
clock running on central time and the city running on 'daylight saving'
time, a third hand was added to the dial of the courthouse clock."
-- Ohio news in brief. The Cedarville Herald. 1920-05-21;43(21):1 (col. 5)
https://digitalcommons.cedarville.edu/cedarville_herald/794

Canada

Attached to: America/Coral_Harbour (backzone)

Paul Eggert (2018-03-18):

America/Palm_Springs would be tricky, as it kept two sets of clocks
in 1946/7.  See the following notes.

Attached to: America/Port_of_Spain (backzone)

Steve Allen (2018-01-19):

The shadow of Mt. San Jacinto brings darkness very early in the winter
months.  In 1946 the chamber of commerce decided to put the clocks of Palm
Springs forward by an hour in the winter.
https://www.desertsun.com/story/life/2017/12/27/palm-springs-struggle-daylight-savings-time-and-idea-sun-time/984416001/
Desert Sun, Number 18, 1 November 1946
https://cdnc.ucr.edu/cgi-bin/cdnc?a=d&d=DS19461101
has proposal for meeting on front page and page 21.
Desert Sun, Number 19, 5 November 1946
https://cdnc.ucr.edu/cgi-bin/cdnc?a=d&d=DS19461105
reports that Sun Time won at the meeting on front page and page 5.
Desert Sun, Number 37, 7 January 1947
https://cdnc.ucr.edu/cgi-bin/cdnc?a=d&d=DS19470107.2.12
front page reports request to abandon Sun Time and page 7 notes a "class war".
Desert Sun, Number 38, 10 January 1947
https://cdnc.ucr.edu/cgi-bin/cdnc?a=d&d=DS19470110
front page reports on end.

Trinidad and Tobago

Attached to: America/Port_of_Spain (backzone)

Paul Eggert (2018-11-18):

Alan Eugene Davis writes (1996-03-16),
"I am certain, having lived there for the past decade, that 'Truk'
(now properly known as Chuuk) ... is in the time zone GMT+10."
Shanks & Pottenger write that Truk switched from UT +10 to +11
on 1978-10-01; ignore this for now.

Attached to: Pacific/Chuuk (backzone)