AST time now |
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16:49:39 Fri, 27 Jun 2025
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| UTC Offset: UTC -4 |
Atlantic Standard Time (AST) operates at UTC−4 and is primarily used in parts of the Caribbean, Atlantic Canada, and a small region of Greenland during the non-daylight saving months. It is also known simply as "Atlantic Time". In regions that observe daylight saving time, AST typically shifts to Atlantic Daylight Time (ADT, UTC−3) during the summer months. AST is a fixed time zone that stays one hour ahead of Eastern Standard Time (EST, UTC−5).
Importance and Global Use of AST
AST is important for providing a unified time zone across island nations, coastal regions, and territories bordering the Atlantic Ocean. It helps synchronize activities such as government operations, public services, education, and transportation across multiple islands and regions that rely heavily on shared scheduling and interconnectivity.
Globally, AST plays a role in coordinating international tourism, aviation, and shipping in the Atlantic region. It also supports offshore financial services and telecommunications, especially for countries and territories that engage in trade with North America and Europe. Its placement between North and South American time zones allows it to serve as a bridge for regional communication and scheduling.
Where and When AST is used worldwide
North America
Canadian provinces using AST all year
- Quebec (areas east of 63°W longitude)
Canadian provinces using AST during winter and ADT during summer
- Most of mainland Labrador, in the province of Newfoundland and Labrador
- Nova Scotia
- New Brunswick
- Prince Edward Island
Areas of Greenland using AST during winter and ADT during summer
- Thule Air Base
Atlantic
Atlantic islands and territories using AST during winter and ADT during summer
- Bermuda
Caribbean
Caribbean countries and territories using AST all year
- Anguilla
- Antigua and Barbuda
- Aruba
- Barbados
- British Virgin Islands
- Caribbean Netherlands
- Curaçao
- Dominica
- Dominican Republic
- Grenada
- Guadeloupe
- Martinique
- Montserrat
- Puerto Rico
- Saint Barthélemy
- Saint Kitts and Nevis
- Saint Lucia
- Saint Martin (FR)
- Saint Vincent and the Grenadines
- Sint Maarten (NL)
- Trinidad and Tobago
- U.S. Virgin Islands
Other Time Zones in UTC -4
Other time zones share the same offset as Atlantic Standard Time (AST), but are known by different names. While their clocks align, they may represent different regions or countries based on local time zone definitions.
- Amazon Time – AMT
- Bolivia Time – BOT
- Cuba Daylight Time – CDT
- Chile Standard Time – CLT
- Eastern Daylight Time – EDT
- Guyana Time – GYT
- Paraguay Time – PYT
- Venezuelan Standard Time – VET