Africa/Sao_Tome

Time zone identifier: Africa/Sao_Tome

Current civil offset: +00:00 (GMT)

Current DST state: Observing Standard Time

First standard time adoption: Adopted on 1883-12-31

Local Mean Time (LMT): +00:26:56 based on geographic meridian

Total recorded transitions: 4 transitions across 4 distinct offsets

Associated countries: ST

Historical Offset Step Chart (1880 to Present)

Text summary: Africa/Sao_Tome shifted between 4 distinct offsets from 1883-12-31 through the modern era.

Complete Transition History (4 Transitions)

UTC Instant	Local Wall Time	Shift	Abbreviation	DST	Effect
`1883-12-31T23:33:04Z`	`1883-12-31 22:56:19`	+00:26:56 → -00:36:45	`LMT`	No	overlap
`1912-01-01T00:00:00Z`	`1912-01-01 00:00:00`	-00:36:45 → +00:00	`GMT`	No	gap
`2018-01-01T01:00:00Z`	`2018-01-01 02:00:00`	+00:00 → +01:00	`WAT`	No	gap
`2019-01-01T01:00:00Z`	`2019-01-01 01:00:00`	+01:00 → +00:00	`GMT`	No	overlap

Notes from the Maintainers

Source: africa (Lines 1150 to 1170)

São Tomé and Príncipe

See Europe/Lisbon for info about the 1912 transition.

From Steffen Thorsen (2018-01-08):
Multiple sources tell that São Tomé changed from UTC to UTC+1 as
they entered the year 2018.
From 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

From 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/

From 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.]

Attributed Statements:

Steffen Thorsen (2018-01-08):

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

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

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/

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.]

Methodology Note: The 1970 Rule

tzdb guarantees accuracy for timestamps from 1970 onwards. Transitions prior to 1970 represent best-effort historical reconstructions.