Time Zone Changes in 2024

Tim Parenti (2024-07-01):

For timestamps before independence, see commentary for Europe/Lisbon.
Shanks gives 1907 instead for the transition to -02.

Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]

Attached to: Atlantic/Cape_Verde (africa)

Tim Parenti (2024-07-01):

For timestamps before independence, see commentary for Europe/Lisbon.

Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]

Attached to: Africa/Bissau (africa)

Tim Parenti (2024-07-01):

For timestamps before Mozambique's independence, see commentary for
Europe/Lisbon.

Attached to: Africa/Maputo (africa)

Paul Eggert (2024-05-24):

The London Gazette, 1903-04-03, page 2245, says that
as of 1903-03-03 a time ball at the port of Lourenço Marques
(as Maputo was then called) was dropped daily at 13:00:00 LMT,
corresponding to 22:49:41.7 GMT, so local time was +02:10:18.3.
Conversely, the newspaper South Africa, 1909-02-09, page 321,
says the port had just installed an apparatus that communicated
"from the controlling clock in the new Observatory at Reuben Point ...
exact mean South African time, i.e., 30 deg., or 2 hours East of Greenwich".
Although Shanks gives 1903-03-01 for the transition to CAT,
evidently the port transitioned to CAT after 1903-03-03 but before
the Portuguese legal transition of 1912-01-01 (see Europe/Lisbon commentary).
For lack of better info, list 1909 as the transition date.

Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
STDOFF	2:10:18.3

Attached to: Africa/Maputo (africa)

Tim Parenti (2024-07-01):

The 1912-01-01 transition occurred at 00:00 new time, per the 1911-05-24
Portuguese decree (see Europe/Lisbon).  A provision in article 5(c) of the
decree prescribed that Timor "will keep counting time in harmony with
neighboring foreign colonies, [for] as long as they do not adopt the time
that belongs to them in [the Washington Convention] system."

See Indonesia for the 1945 transition.

From João Carrascalão, brother of the former governor of East Timor, in
East Timor may be late for its millennium
<https://etan.org/et99c/december/26-31/30ETMAY.htm> (1999-12-26/31):
Portugal tried to change the time forward in 1974 because the sun
rises too early but the suggestion raised a lot of problems with the
Timorese and I still don't think it would work today because it
conflicts with their way of life.

Attached to: Asia/Dili (asia)

Zhanbolat Raimbekov (2024-01-19):

Kazakhstan (all parts) switching to UTC+5 on March 1, 2024
https://www.gov.kz/memleket/entities/mti/press/news/details/688998?lang=ru
[in Russian]
(2024-01-20): https://primeminister.kz/ru/decisions/19012024-20

Attached to: Asia/Almaty (asia)

Alexander Krivenyshev (2024-01-19):

According to a different news and the official web site for the Ministry of
Trade and Integration of the Republic of Kazakhstan:
https://en.inform.kz/news/kazakhstan-to-switch-to-single-hour-zone-mar-1-54ad0b/

Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]

Almaty (formerly Alma-Ata), representing most locations in Kazakhstan
This includes Abai/Abay (ISO 3166-2 code KZ-10), Aqmola/Akmola (KZ-11),
Almaty (KZ-19), Almaty city (KZ-75), Astana city (KZ-71),
East Kazakhstan (KZ-63), Jambyl/Zhambyl (KZ-31), Jetisu/Zhetysu (KZ-33),
Karaganda (KZ-35), North Kazakhstan (KZ-59), Pavlodar (KZ-55),
Shymkent city (KZ-79), Turkistan (KZ-61), and Ulytau (KZ-62).

Attached to: Asia/Almaty (asia)

Heitor David Pinto (2024-06-23):

Sources about time zones in Mongolia seem to list one of two conflicting
configurations.  The first configuration, mentioned in a comment to the TZ
database in 1999, citing a Mongolian government website, lists the provinces
of Bayan-Ölgii, Khovd and Uvs in UTC+7, and the rest of the country in
UTC+8.  The second configuration, mentioned in a comment to the database in
2001, lists Bayan-Ölgii, Khovd, Uvs, Govi-Altai and Zavkhan in UTC+7, Dornod
and Sükhbaatar in UTC+9, and the rest of the country in UTC+8.

The first configuration is still mentioned by several Mongolian travel
agencies:
https://www.adventurerider.mn/en/page/about_mongolia
http://www.naturetours.mn/nt/mongolia.php
https://www.newjuulchin.mn/web/content/7506?unique=fa24a0f6e96e022a3578ee5195ac879638c734ce

It also matches these flight schedules in 2013:
http://web.archive.org/web/20130722023600/https://www.hunnuair.com/en/timetabled
The flight times imply that the airports of Uliastai (Zavkhan), Choibalsan
(Dornod) and Altai (Govi-Altai) are in the same time zone as Ulaanbaatar,
and Khovd is one hour behind....

The second configuration was mentioned by an official of the Mongolian
standards agency in an interview in 2014: https://ikon.mn/n/9v6
And it's still listed by the Mongolian aviation agency:
https://ais.mn/files/aip/eAIP/2023-12-25/html/eSUP/ZM-eSUP-23-04-en-MN.html

... I believe that the first configuration is what is actually observed in
Mongolia and has been so all along, at least since 1999.  The second
configuration closely matches the ideal time zone boundaries at 97.5° E and
112.5° E but it doesn't seem to be used in practice.

Attached to: Mongol (asia)

Heba Hamad (2024-01-25):

the summer time for the years 2024,2025 will begin in Palestine
from Saturday at 02:00 AM by 60 minutes forward as shown below:
year date
2024 2024-04-20
2025 2025-04-12

Attached to: EgyptAsia (asia)

Paul Eggert (2024-01-25):

For now, guess that spring and fall transitions will normally
continue to use 2022's rules, that during DST Palestine will switch
to standard time at 02:00 the last Saturday before Ramadan and back
to DST at 02:00 the second Saturday after Ramadan, and that
if the normal spring-forward or fall-back transition occurs during
Ramadan the former is delayed and the latter advanced.
To implement this, I predicted Ramadan-oriented transition dates for
2026 through 2086 by running the following program under GNU Emacs 29.2,
with the results integrated by hand into the table below.
Predictions after 2086 are approximated without Ramadan.

(let ((islamic-year 1447))
(require 'cal-islam)
(while (< islamic-year 1510)
(let ((a (calendar-islamic-to-absolute (list 9 1 islamic-year)))
(b (+ 1 (calendar-islamic-to-absolute (list 10 1 islamic-year))))
(saturday 6))
(while (/= saturday (mod (setq a (1- a)) 7)))
(while (/= saturday (mod b 7))
(setq b (1+ b)))
(setq b (+ 7 b))
(setq a (calendar-gregorian-from-absolute a))
(setq b (calendar-gregorian-from-absolute b))
(insert
(format
(concat "Rule Palestine\t%d\tonly\t-\t%s\t%2d\t2:00\t0\t-\n"
"Rule Palestine\t%d\tonly\t-\t%s\t%2d\t2:00\t1:00\tS\n")
(car (cdr (cdr a))) (calendar-month-name (car a) t) (car (cdr a))
(car (cdr (cdr b))) (calendar-month-name (car b) t) (car (cdr b)))))
(setq islamic-year (+ 1 islamic-year))))

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

Attached to: EgyptAsia (asia)

Paul Eggert (2024-01-21):

The Spanish initially used American (west-of-Greenwich) time.
It is unknown what time Manila kept when the British occupied it from
1762-10-06 through 1764-04; for now assume it kept American time.
On 1844-08-16, Narciso Clavería, governor-general of the
Philippines, issued a proclamation announcing that 1844-12-30 was to
be immediately followed by 1845-01-01; see R.H. van Gent's
History of the International Date Line
https://webspace.science.uu.nl/~gent0113/idl/idl_philippines.htm

Attached to: Phil (asia)

Paul Eggert (2024-09-05):

The penultimate URL in P Chan's email refers to page 521 of
Selga M, The Time Service in the Philippines.
Proc Pan-Pacific Science Congress. Vol. 1 (1923), 519-532.
It says, "The change from the meridian 120° 58' 04" to the 120th implied a
change of 3 min. 52s.26 in time; consequently on 6th September, 1899,
Manila Observatory gave the noon signal 3 min. 52s.26 later than before".

Wikipedia says the US declared Manila liberated on March 4, 1945;
this doesn't affect clocks, just our time zone abbreviation and DST flag.

From Paul Goyette (2018-06-15) with URLs updated by Guy Harris (2024-02-15):
In the Philippines, there is a national law, Republic Act No. 10535
which declares the official time here as "Philippine Standard Time".
The act [1] even specifies use of PST as the abbreviation, although
the FAQ provided by PAGASA [2] uses the "acronym PhST to distinguish
it from the Pacific Standard Time (PST)."
[1] https://www.officialgazette.gov.ph/2013/05/15/republic-act-no-10535/
[2] https://prsd.pagasa.dost.gov.ph/index.php/28-astronomy/302-philippine-standard-time

Attached to: Phil (asia)

Stuart Bishop (2024-11-12):

An article discussing the in-use but technically unofficial timezones
in the Western Australian portion of the Nullarbor Plain.
https://www.abc.net.au/news/2024-11-22/outback-wa-properties-strange-time-zones/104542494

Paul Eggert (2024-11-12):

As the article says, the Eyre Bird Observatory and nearby sheep stations
can use Tokyo time.  Other possibilities include Asia/Chita, Asia/Seoul,
and Asia/Jayapura.

Queensland

Ivan Benovic (2024-01-30):

https://www.slov-lex.sk/pravne-predpisy/SK/ZZ/1946/54/
(This is an official link to the Czechoslovak Summer Time Act of
March 8, 1946 that authorizes the Czechoslovak government to set the
exact dates of change to summer time and back to Central European Time.
The act also implicitly confirms Central European Time as the
official time zone of Czechoslovakia and currently remains in force
in both the Czech Republic and Slovakia.)
https://www.psp.cz/eknih/1945pns/tisky/t0216_00.htm
(This is a link to the original legislative proposal dating back to
February 22, 1946. The accompanying memorandum to the proposal says
that an advisory committee on European railroad transportation that
met in Brussels in October 1945 decided that the change of time
should be carried out in all participating countries in a strictly
coordinated manner....)

Attached to: Czech (europe)

Paul Eggert (2024-01-30):

The source for Czech data is: Kdy začíná a končí letní čas.
https://kalendar.beda.cz/kdy-zacina-a-konci-letni-cas
Its main text disagrees with its quoted sources only in 1918,
where the main text says spring and autumn transitions
occurred at 02:00 and 03:00 respectively (as usual),
whereas the 1918 source "Oznámení o zavedení letního času v roce 1918"
says transitions were at 01:00 and 02:00 respectively.
As the 1918 source appears to be a humorous piece, and it is
unlikely that Prague would have disagreed with its neighbors by an hour,
go with the main text for now.

We know of no English-language name for historical Czech winter time;
abbreviate it as "GMT", as it happened to be GMT.

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

Attached to: Czech (europe)

Tim Parenti (2024-07-01):

Decreto 1469 of 1915-03-30 ... had nothing to do with DST;
rather it regulated the sending of time signals.
But we do see linkage to Spain in the 1920s below.
https://dre.pt/dr/detalhe/decreto/1469-1915-285721
https://dre.pt/application/conteudo/285721

According to the Observatory, standard time was first advanced by Decreto
2433 of 1916-06-09 and restored by Decreto 2712 of 1916-10-28.  While Whitman
gives 1916-10-31 for the latter transition, Shanks & Pottenger agrees more
closely with the decree, which stated that its provision "will start sixty
minutes after the end of 31 October, according to the current time," i.e.,
01:00 on 1 November.
https://dre.pt/dr/detalhe/decreto/2433-1916-267192
https://dre.pt/application/conteudo/267192
https://dre.pt/dr/detalhe/decreto/2712-1916-590937
https://dre.pt/application/conteudo/590937

Attached to: Port (europe)

Tim Parenti (2024-07-01):

Article 7 of Decreto 2922 of 1916-12-30 stated that "the legal time will be
advanced by sixty minutes from 1 March to 31 October."  Per Article 15, this
came into force from 1917-01-01.  Just before the first fall back, Decreto
3446 of 1917-10-11 changed the annual end date to 14 October.
https://dre.pt/dr/detalhe/decreto/2922-1916-261894
https://dre.pt/application/conteudo/261894
https://dre.pt/dr/detalhe/decreto/3446-1917-495161
https://dre.pt/application/conteudo/495161
This annual change was revoked by Decreto 8038 of 1922-02-18.
https://dre.pt/dr/detalhe/decreto/8038-1922-569751
https://dre.pt/application/conteudo/569751

Attached to: Port (europe)

Tim Parenti (2024-07-01):

Decreto 9592 of 1924-04-14 noted that "France maintains the advance of legal
time in the summer and Spain has now adopted it for the first time" and
considered "that the absence of similar measures would cause serious
difficulties for international rail connections with consequent repercussions
on domestic service hours..." along with "inconvenient analogues...for postal
and telegraph services."  Summer time would be in effect from 17 April to 4
October, with the spring change explicitly specified by bringing clocks
forward from 16 April 23:00.
https://dre.pt/dr/detalhe/decreto/9592-1924-652133
https://dre.pt/application/conteudo/652133

Decreto 10700, issued 1925-04-16, noted that Spain had not continued summer
time, declared that "the current legal hour prior to 17 April remains
unchanged from that day forward", and revoked legislation to the contrary,
just a day before summer time would have otherwise resumed.
https://dre.pt/dr/detalhe/decreto/10700-1925-437826
https://dre.pt/application/conteudo/437826

Attached to: Port (europe)

Tim Parenti (2024-07-01):

Portaria 9465 of 1940-02-17 advanced clocks from Saturday 1940-02-24 23:00.
The clocks were restored by Portaria 9658, issued Monday 1940-10-07,
effective from 24:00 that very night, which agrees with Shanks & Pottenger;
Whitman gives Saturday 1940-10-05 instead.
https://dre.pt/dr/detalhe/portaria/9465-1940-189096
https://dre.pt/application/conteudo/189096
https://dre.pt/dr/detalhe/portaria/9658-1940-196729
https://dre.pt/application/conteudo/196729

Attached to: Port (europe)

Tim Parenti (2024-07-01):

The Astronomical Observatory of Lisbon cites Portaria 11767 of 1947-03-28 for
1947 and Portaria 12286 of 1948-02-19 for 1948.
https://dre.pt/dr/detalhe/portaria/11767-1947-414787
https://dre.pt/application/conteudo/414787
https://dre.pt/dr/detalhe/portaria/12286-1948-152953
https://dre.pt/application/conteudo/152953

Although the latter ordinance explicitly had the 1948-10-03 transition
scheduled for 02:00 rather than 03:00 as had been used in 1947, Decreto-Lei
37048 of 1948-09-07 recognized "that it is advisable to definitely set...the
'summer time' regime", and fixed the fall transition at 03:00 moving forward.
https://dre.pt/dr/detalhe/decreto-lei/37048-1948-373810
https://dre.pt/application/conteudo/373810
While the Observatory only cites this act for 1949-1965 and not for 1948, it
does not appear to have had any provision delaying its effect, so assume that
it overrode the prior ordinance for 1948-10-03.

Whitman says DST was not observed in 1950 and gives Oct lastSun for 1952 on.
The Observatory, however, agrees with Shanks & Pottenger that 1950 was not an
exception and that Oct Sun>=1 was maintained through 1965.

Attached to: Port (europe)

Tim Parenti (2024-07-01):

Decreto-Lei 47233 of 1966-10-01 considered that the "duality" in time was
"the cause of serious disturbances" and noted that "the countries with which
we have the most frequent contacts...have already adopted" a solution
coinciding with the extant "summer time".  It established that the former
"summer time" would apply year-round on the mainland and adjacent islands
with immediate effect, as the fall back would have otherwise occurred later
that evening.
https://dre.pt/dr/detalhe/decreto-lei/47233-1966-293729
Model this by changing zones without changing clocks at the
previously-appointed fall back time.

Decreto-Lei 309/76 of 1976-04-27 acknowledged that those international
contacts had returned to adopting seasonal times, and considered that the
year-round advancement "entails considerable sacrifices for the vast majority
of the working population during the winter months", including morning
visibility concerns for schoolchildren.  It specified, beginning 1976-09-26
01:00, an annual return to UT+00 on the mainland from 00:00 UT on Sep lastSun
to 00:00 UT on Mar lastSun (unless the latter date fell on Easter, in which
case it was to be brought forward to the preceding Sunday).  It also assigned
the Permanent Time Commission to study and propose revisions for the Azores
and Madeira, neither of which resumed DST until 1982 (as described further
below).
https://dre.pt/dr/detalhe/decreto-lei/309-1976-502063

Attached to: Port (europe)

Tim Parenti (2024-07-01):

Beginning in 1978, rather than triggering the Easter rule of the 1976 decree
(Easter fell on 1978-03-26), Article 5 was used instead, which allowed DST
dates to be changed by order of the Minister of Education and Scientific
Research, upon consultation with the Permanent Time Commission, "whenever
considered convenient."  As such, a series of one-off ordinances were
promulgated for the mainland in 1978 through 1980, after which the 1976
decree naturally came back into force from 1981.

Attached to: Port (europe)

Tim Parenti (2024-07-01):

Decreto-Lei 44-B/86 of 1986-03-07 switched mainland Portugal's transition
times from 0:00s to 1:00u to harmonize with the EEC from 1986-03-30.
https://dre.pt/dr/detalhe/decreto-lei/44-b-1986-628280
(Transitions of 1:00s as previously reported and used by the W-Eur rules,
though equivalent, appear to have been fiction here.)  Madeira continued to
use 0:00s for spring 1986 before joining with the mainland using 1:00u in the
fall; meanwhile, in the Azores the two were equivalent, so the law specifying
0:00s wasn't touched until 1992.  (See below for more on the islands.)

Attached to: Europe/Lisbon (europe)

Tim Parenti (2024-07-01):

For the Azores and Madeira, legislation was followed from the laws currently
in force as listed at:
https://oal.ul.pt/hora-legal/legislacao/
working backward through references of revocation and abrogation to
Decreto-Lei 47233 of 1966-10-01, the last time DST was abolished across the
mainland and its adjacent islands.

Attached to: Atlantic/Azores (europe)

Tim Parenti (2024-07-01):

While Decreto-Lei 309/76 of 1976-04-27 reintroduced DST on the mainland by
falling back on 1976-09-26, it assigned the Permanent Time Commission to
study and propose revisions for the Azores and Madeira.  Decreto Regional
9/77/A of 1977-05-17 affirmed that "the legal time remained unchanged in the
Azores" at UT-1, and would remain there year-round.
https://dre.pt/dr/detalhe/decreto-regional/9-1977-252066

Decreto Regional 2/82/A, published 1982-03-02, adopted DST in the same
fashion as the mainland used at the time.
https://dre.pt/dr/detalhe/decreto-regional/2-1982-599965
Though transitions in the Azores officially remained at 0:00s through 1992,
this was equivalent to the EU-style 1:00u adopted by the mainland in 1986, so
model it as such.
Rearguard section, for parsers lacking %z; see ziguard.awk.
-2:00	Port	-02/-01	1942 Apr 25 22:00s
-2:00	Port	+00	1942 Aug 15 22:00s
-2:00	Port	-02/-01	1943 Apr 17 22:00s
-2:00	Port	+00	1943 Aug 28 22:00s
-2:00	Port	-02/-01	1944 Apr 22 22:00s
-2:00	Port	+00	1944 Aug 26 22:00s
-2:00	Port	-02/-01	1945 Apr 21 22:00s
-2:00	Port	+00	1945 Aug 25 22:00s
-2:00	Port	-02/-01	1966 Oct  2  2:00s
-1:00	-	-01	1982 Mar 28  0:00s
-1:00	Port	-01/+00	1986
End of rearguard section.

Attached to: Atlantic/Madeira (europe)

Tim Parenti (2024-07-01):

After mainland Portugal had shifted forward an hour from 1992-09-27, Decreto
Legislativo Regional 29/92/A of 1992-12-23 sought to "reduce the time
difference" by shifting the Azores forward as well from 1992-12-27.  Just six
months later, this was revoked by Decreto Legislativo Regional 9/93/A, citing
"major changes in work habits and way of life."  Though the revocation didn't
give a transition time, it was signed Wednesday 1993-06-16; assume it took
effect later that evening, and that an EU-style spring forward (to +01) was
still observed in the interim on 1993-03-28.
https://dre.pt/dr/detalhe/decreto-legislativo-regional/29-1992-621553
https://dre.pt/dr/detalhe/decreto-legislativo-regional/9-1993-389633

Attached to: Atlantic/Madeira (europe)

Tim Parenti (2024-07-01):

Decreto Regional 5/82/M, published 1982-04-03, established DST transitions at
0:00u, which for Madeira is equivalent to the mainland's rules (0:00s) at the
time.  It came into effect the day following its publication, Sunday
1982-04-04, thus resuming Madeira's DST practice about a week later than the
mainland and the Azores.
https://dre.pt/dr/detalhe/decreto-regional/5-1982-608273

Decreto Legislativo Regional 18/86/M, published 1986-10-01, adopted EU-style
rules (1:00u) and entered into immediate force after being signed on
1986-07-31.
https://dre.pt/dr/detalhe/decreto-legislativo-regional/18-1986-221705

Romania

Attached to: Romania (europe)

Paul Eggert (2024-05-24):

Express BMT as 0:29:45.500, approximately the same precision 7° 26' 22.50".

We can find no reliable source for Shanks's assertion that all of Switzerland
except Geneva switched to Bern Mean Time at 00:00 on 1848-09-12.  This book:

Jakob Messerli. Gleichmässig, pünktlich, schnell. Zeiteinteilung und
Zeitgebrauch in der Schweiz im 19. Jahrhundert. Chronos, Zurich 1995,
ISBN 3-905311-68-2, OCLC 717570797.

suggests that the transition was more gradual, and that the Swiss did not
agree about civil time during the transition.  The timekeeping it gives the
most detail for is postal and telegraph time: here, federal legislation (the
"Bundesgesetz über die Erstellung von elektrischen Telegraphen") passed on
1851-11-23, and an official implementation notice was published 1853-07-16
(Bundesblatt 1853, Bd. II, S. 859).  On p 72 Messerli writes that in
practice since July 1853 Bernese time was used in "all postal and telegraph
offices in Switzerland from Geneva to St. Gallen and Basel to Chiasso"
(Google translation).  For now, model this transition as occurring on
1853-07-16, though it probably occurred at some other date in Zurich, and
legal civil time probably changed at still some other transition date.

Attached to: Swiss (europe)

Paul Eggert (2024-11-18):

Dowd's proposal left many details unresolved, such as where to draw
lines between time zones.  Sandford Fleming of the Canadian Pacific Railway
argued for Dowd's proposal in 1876, and Cleveland Abbe of the American
Meteorology Society published a report in 1879 recommending four US time
zones based on GMT.  However, the key individual who made time zones
work in the US was William Frederick Allen - railway engineer,
managing editor of the Travelers' Guide, and secretary of the
General Time Convention, a railway standardization group.  Allen
spent months in dialogs with scientific and railway leaders,
developed a workable plan to institute time zones, and presented it
to the General Time Convention on 1883-04-11, saying that his plan
meant "local time would be practically abolished" - a plus for
railway scheduling.  By the next convention on 1883-10-11 nearly all
railroads had agreed and it took effect on 1883-11-18.  That Sunday
was called the "day of two noons", as some locations observed noon
twice.  Allen witnessed the transition in New York City, writing:

I heard the bells of St. Paul's strike on the old time.  Four
minutes later, obedient to the electrical signal from the Naval
Observatory ... the time-ball made its rapid descent, the chimes
of old Trinity rang twelve measured strokes, and local time was
abandoned, probably forever.

Most of the US soon followed suit.  See:
Bartky IR. The adoption of standard time. Technol Cult 1989 Jan;30(1):25-56.
https://dx.doi.org/10.2307/3105430

Attached to: US (northamerica)

Chris Walton (2024-01-09):

The [Toronto] changes in 1947, 1948, and 1949 took place at 2:00 a.m. local
time instead of midnight....  Toronto Daily Star - ...
April 2, 1947 - Page 39 ... April 7, 1948 - Page 13 ...
April 2, 1949 - Page 1 ... April 7, 1949 - Page 24 ...
November 25, 1949 - Page 52 ... April 21, 1950 - Page 14 ...
September 19, 1950 - Page 46 ... September 20, 1950 - Page 3 ...
November 24, 1950 - Page 21

Attached to: Toronto (northamerica)

Heitor David Pinto (2024-08-04):

In 1931, the decree implementing DST specified that it would take
effect on 30 April....
https://www.dof.gob.mx/nota_to_imagen_fs.php?cod_diario=192270&pagina=2&seccion=1

In 1981, the decree changing Campeche, Yucatán and Quintana Roo to UTC-5
specified that it would enter into force on 26 December 1981 at 2:00....
https://www.dof.gob.mx/nota_to_imagen_fs.php?codnota=4705667&fecha=23/12/1981&cod_diario=202796

In 1982, the decree returning Campeche and Yucatán to UTC-6 specified that
it would enter into force on 2 November 1982 at 2:00....
https://www.dof.gob.mx/nota_to_imagen_fs.php?cod_diario=205689&pagina=3&seccion=0

Quintana Roo changed to UTC-6 on 4 January 1983 at 0:00, and again
to UTC-5 on 26 October 1997 at 2:00....
https://www.dof.gob.mx/nota_to_imagen_fs.php?codnota=4787355&fecha=28/12/1982&cod_diario=206112
https://www.dof.gob.mx/nota_to_imagen_fs.php?cod_diario=209559&pagina=15&seccion=0

Durango, Coahuila, Nuevo León and Tamaulipas were set to UTC-7 on 1 January
1922, and changed to UTC-6 on 10 June 1927.  Then Durango, Coahuila and
Nuevo León (but not Tamaulipas) returned to UTC-7 on 15 November 1930,
observed DST in 1931, and changed again to UTC-6 on 1 April 1932....
https://www.dof.gob.mx/nota_to_imagen_fs.php?codnota=4441846&fecha=29/12/1921&cod_diario=187468
https://www.dof.gob.mx/nota_to_imagen_fs.php?codnota=4541520&fecha=09/06/1927&cod_diario=193920
https://www.dof.gob.mx/nota_to_imagen_fs.php?codnota=4491963&fecha=15/11/1930&cod_diario=190835
https://www.dof.gob.mx/nota_to_imagen_fs.php?codnota=4418437&fecha=21/01/1932&cod_diario=185588

... the ... 10 June 1927 ... decree only said 10 June 1927, without
specifying a time, so I suppose that it should be considered at 0:00.
https://www.dof.gob.mx/nota_to_imagen_fs.php?codnota=4541520&fecha=09/06/1927&cod_diario=193920

In 1942, the decree changing Baja California, Baja California Sur, Sonora,
Sinaloa and Nayarit to UTC-7 was published on 24 April, but it said that it
would apply from 1 April, so it's unclear when the change actually
occurred. The database currently shows 24 April 1942.
https://www.dof.gob.mx/nota_to_imagen_fs.php?cod_diario=192203&pagina=2&seccion=1

Baja California Sur, Sonora, Sinaloa and Nayarit never used UTC-8.  The ...
14 January 1949 ... change [to UTC-8] only occurred in Baja California.
https://www.dof.gob.mx/nota_to_imagen_fs.php?codnota=4515613&fecha=13/01/1949&cod_diario=192309

In 1945, the decree changing Baja California to UTC-8 specified that it
would take effect on the third day from its publication.
It was published on 12 November, so it would take effect on 15 November....
https://www.dof.gob.mx/nota_to_imagen_fs.php?codnota=4555049&fecha=12/11/1945&cod_diario=194763

In 1948, the decree changing Baja California to UTC-7 specified that it
would take effect on "this date".  The decree was made on 13 March,
but published on 5 April, so it's unclear when the change actually occurred.
The database currently shows 5 April 1948.
https://www.dof.gob.mx/nota_to_imagen_fs.php?cod_diario=188624&pagina=2&seccion=0

In 1949, the decree changing Baja California to UTC-8 was published on 13
January, but it said that it would apply from 1 January, so it's unclear when
the change actually occurred.  The database currently shows 14 January 1949.
https://www.dof.gob.mx/nota_to_imagen_fs.php?codnota=4515613&fecha=13/01/1949&cod_diario=192309

Baja California also observed UTC-7 from 1 May to 24 September 1950,
from 29 April to 30 September 1951 at 2:00,
and from 27 April to 28 September 1952 at 2:00....
https://www.dof.gob.mx/nota_to_imagen_fs.php?codnota=4600403&fecha=29/04/1950&cod_diario=197505
https://www.dof.gob.mx/nota_to_imagen_fs.php?codnota=4623553&fecha=23/09/1950&cod_diario=198805
https://www.dof.gob.mx/nota_to_imagen_fs.php?codnota=4469444&fecha=27/04/1951&cod_diario=189317
https://www.dof.gob.mx/nota_to_imagen_fs.php?codnota=4533868&fecha=10/03/1952&cod_diario=193465

All changes in Baja California from 1948 to 1952 match those in California,
on the same dates or with a difference of one day.
So it may be easier to implement these changes as DST with rule CA
during this whole period.

Attached to: Mexico (northamerica)

Heitor David Pinto (2024-09-24):

Today the Congress of Paraguay passed a bill to observe UTC-3 permanently....
The text of the bill says that it would enter into force on the first
Sunday in October 2024, the same date currently scheduled to start DST....
https://silpy.congreso.gov.py/web/expediente/132531
(2024-10-14):
The president approved the law on 11 October 2024,
and it was officially published on 14 October 2024.
https://www.gacetaoficial.gov.py/index/detalle_publicacion/89723
The text of the law says that it enters into force on the first
Sunday in October 2024 (6 October 2024).  But the constitution
prohibits retroactive effect, and the civil code says that laws
enter into force on the day after their publication or on the day
that they specify, and it also says that they don't have retroactive
effect.  So I think that the time change on 6 October 2024 should
still be considered as DST according to the previous law, and
permanently UTC-3 from 15 October 2024 according to the new law....
https://www.constituteproject.org/constitution/Paraguay_2011
https://www.oas.org/dil/esp/codigo_civil_paraguay.pdf

Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]

Attached to: America/Asuncion (southamerica)

Tim Parenti (2024-07-01):

For timestamps before independence, see commentary for Europe/Lisbon.

Attached to: Africa/Luanda (backzone)

Paul Eggert (2024-05-22):

The following zones pretend that standard time extends backward
indefinitely into the past, and so are ahistorical.
In current TZDB these entries are links to geographical locations
that agree with the ahistorical zones since 1970.
These are in numeric rather than alphabetic order.

Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]

Attached to: HST (backzone)