The Atlantic Standard Time Zone (AST) is a geographic region that keeps time by subtracting four hours from Coordinated Universal Time (UTC).

In Canada, the provinces of New Brunswick, Prince Edward Island, and Nova Scotia are part of the Atlantic Standard Time Zone. Officially, the entirety of Labrador is also in the Atlantic Standard Time Zone; however, the southeastern tip of that region unofficially uses Newfoundland Standard Time, the time used on the island of Newfoundland.

Other parts of the world that keep time by subtracting four hours from UTC include Bermuda, Puerto Rico, the US Virgin Islands, and many other Caribbean islands, as well as Venezuela, parts of Brazil and Argentina.

AST is known as Atlantic Daylight Time (ADT) during daylight saving time, and has one hour added to make it three hours behind UTC (UTC -3).

See also

• Time zone
• Hawaii-Aleutian Standard Time Zone
• Alaska Standard Time Zone
• Pacific Standard Time Zone
• Mountain Standard Time Zone
• Central Standard Time Zone
• Eastern Standard Time Zone
• Newfoundland Standard Time Zone

Sources

• World time zone map
• U.S. time zone map
• History of U.S. time zones and UTC conversion
• Canada time zone map
• Time zones for major world cities