Africa/Sao_Tome time zone

About Africa/Sao_Tome

Africa/Sao_Tome is the IANA time zone for Sao Tome and Principe. It currently keeps Greenwich Mean Time (GMT, UTC+0) all year.

Its principal location is Sao Tome at 0.33° N, 6.73° E.

Abbreviations in use: GMT. Offset page: UTC+0.

Rule for future years (POSIX TZ string)

GMT0

The standard time is called GMT and is UTC+0. POSIX writes the offset with the opposite sign (west of Greenwich is positive), which is why the string says "0". There is no daylight saving rule: the zone stays on this offset for every year after the end of its explicit transitions. Software that has no full tzdata copy, such as many embedded devices, can use this string directly as the TZ environment variable.

History of Africa/Sao_Tome since 1970

The record starts with local mean time (UTC+0:27), which ended on January 1, 1884. The record shows no daylight saving time at any point.

Before 1970

2 offset changes before 1970 in the record:

• Tuesday, January 1, 1884: UTC+0:27 → UTC−0:37
• Sunday, December 31, 1911: UTC−0:37 → UTC+0 (GMT)

tzdata commits to accuracy from 1970 for every zone (zone1970.tab); earlier entries are historical research and may be incomplete.

Aliases and zones with the same clock

Other zones that keep exactly the same time under the current rules (but have a different history): Africa/Abidjan, Africa/Bissau, Africa/Casablanca, Africa/El_Aaiun, Africa/Monrovia, America/Danmarkshavn.

Places on Africa/Sao_Tome

• São ToméST

Convert Sao Tome time

Using Africa/Sao_Tome in code

Every major platform reads the same IANA ID. Store instants in UTC and convert with the ID at display time; never store a fixed offset for a place that has daylight saving time.

// JavaScript
new Date().toLocaleString('en-US', { timeZone: 'Africa/Sao_Tome' })

# Python 3.9+
from zoneinfo import ZoneInfo
from datetime import datetime
datetime.now(ZoneInfo('Africa/Sao_Tome'))

// Java
java.time.ZonedDateTime.now(java.time.ZoneId.of("Africa/Sao_Tome"))

// Go
loc, _ := time.LoadLocation("Africa/Sao_Tome")
time.Now().In(loc)

-- PostgreSQL
SELECT now() AT TIME ZONE 'Africa/Sao_Tome';

# Shell
TZ='Africa/Sao_Tome' date

Platforms ship their own copy of tzdata and update it on their own schedule. After a rule change, outputs can differ until the platform updates; this page uses tzdata 2026f.

Related

• Time zones of the world
• GMT time
• UTC time
• Time in São Tomé
• Daylight saving time