Time Zone Abbreviations Glossary

Standard time for the US Central zone, including Houston, Chicago, and Dallas. Used from November to March when daylight saving is not in effect.

Daylight saving time for the US Central zone. Used from the second Sunday of March to the first Sunday of November. Houston, Chicago, and Dallas observe CDT during summer.

General label covering both CST and CDT. When someone says 'Central Time,' they mean whichever is currently active — CST in winter, CDT in summer.

Standard time for the US Eastern zone, including New York, Washington D.C., and Miami. One hour ahead of CST.

Daylight saving time for the US Eastern zone. One hour ahead of CDT. Used March through November.

General label for the Eastern zone, covering both EST and EDT depending on the season.

Standard time for the US Pacific zone, including Los Angeles, San Francisco, and Seattle. Two hours behind CST.

Daylight saving time for the US Pacific zone. Two hours behind CDT.

General label for the Pacific zone, covering both PST and PDT.

Standard time for the US Mountain zone, including Denver and Phoenix. Arizona does not observe DST, so it stays on MST year-round.

Daylight saving time for the US Mountain zone (except Arizona). When MDT is active, it matches CST.

General label for the Mountain zone. Arizona stays on MST year-round while other Mountain states switch to MDT in summer.

The time at the Royal Observatory in Greenwich, London. Often used interchangeably with UTC, though technically they differ slightly. Houston is 6 hours behind GMT in winter.

The primary time standard by which the world regulates clocks. All time zones are defined as offsets from UTC. Houston is UTC−6 in winter and UTC−5 in summer.

The UK's daylight saving time, one hour ahead of GMT. Used from late March to late October. Houston is 6 hours behind BST.

Standard time for much of Western and Central Europe, including Paris, Berlin, and Rome. 7 hours ahead of CST.

Daylight saving time for Central Europe. 7 hours ahead of CDT.

The time zone for all of India and Sri Lanka. 11.5 hours ahead of CST. India does not observe daylight saving time.

The time zone for Japan and Korea. 15 hours ahead of CST. Japan does not observe daylight saving time.

Standard time for eastern Australia, including Sydney and Melbourne. 16 hours ahead of CST.

Daylight saving time for eastern Australia. Used October through April (southern hemisphere summer).

Standard time for New Zealand. 18 hours ahead of CST.

Daylight saving time for New Zealand. Used late September through early April.

Time zone for Hawaii. Four hours behind CST. Hawaii does not observe daylight saving time.

Standard time for Alaska. Three hours behind CST.

Daylight saving time for Alaska. Three hours behind CDT.

The time zone for Singapore, Malaysia, and parts of Southeast Asia. 14 hours ahead of CST.

The time zone for Hong Kong and Macau. Same as Singapore Time, 14 hours ahead of CST.

The single time zone for all of China despite its vast size. 14 hours ahead of US Central Standard Time. Context usually makes clear which CST is meant.