Atlantic Standard Time (AST)
Atlantic Standard Time (AST) is UTC−4. It is the standard (winter) time of Nova Scotia, New Brunswick, PEI; Puerto Rico and the Eastern Caribbean (all year); in summer the same area uses ADT (UTC−3).
AST here is Atlantic Standard Time, not Arabia Standard Time.
Convert AST
Where AST is used
Nova Scotia, New Brunswick, PEI; Puerto Rico and the Eastern Caribbean (all year).
Countries on the same offsets
Major cities on America/Halifax
AST and daylight saving time
The next change is on 14 March 2027 at 01:59 local time: clocks go forward one hour, from AST (UTC−4) to ADT (UTC−3).
Convert AST to other time zones
AST FAQ
What is AST?
Atlantic Standard Time (AST) is UTC−4. It is the standard (winter) time of Nova Scotia, New Brunswick, PEI; Puerto Rico and the Eastern Caribbean (all year); in summer the same area uses ADT (UTC−3).
What is the current AST time?
AST is UTC−4. The live clock on this page shows the current Atlantic Standard Time time, updated every second.
What is the difference between AST and ADT?
ADT is one hour ahead of AST. AST is the standard time; ADT is used during daylight saving time.
Which countries use AST?
AST is used in Nova Scotia, New Brunswick, PEI; Puerto Rico and the Eastern Caribbean (all year).
Updated 6 November 2026. Time zone data: IANA tz database.