AST: Atlantic / Arabia Standard Time
Atlantic Standard Time
Sunday, 27th September 2026
What AST actually is
UTC-4 in winter, UTC-3 (ADT) in summer: eastern Canada and much of the Caribbean.
Careful: Atlantic Standard Time is not on AST at the moment. It is currently ADT (UTC-3) because of daylight saving.
AST means 2 different things
This is the whole reason calendar software uses IANA identifiers instead of abbreviations. All of them, live:
Atlantic Standard Time
UTC-4 in winter, UTC-3 (ADT) in summer: eastern Canada and much of the Caribbean.
Clocks go back 1 hour on Sunday, 1st November 2026, at 1:59 am local time (1:00 am after the change).
Arabia Standard Time
UTC+3, all year: Saudi Arabia, Iraq, Kuwait, Qatar, Bahrain, Yemen.
Clocks here do not change: this zone stays on the same offset all year.
Convert AST
Looking for UTC and GMT developer tooling (epoch conversion, ISO 8601, a free time API)? That lives on our sibling site utctime.app.
Other abbreviations
Questions people ask
What time is it in AST right now?
6:22 am (06:22) on Sunday, 27th September 2026, for Atlantic Standard Time. Careful: AST means 2 different things. The other meanings and their current times are listed below.
What does AST stand for?
Atlantic / Arabia Standard Time. UTC-4 in winter, UTC-3 (ADT) in summer: eastern Canada and much of the Caribbean.
What is the UTC offset of AST?
Atlantic Standard Time: UTC-3; Arabia Standard Time: UTC+3.
Why does AST mean more than one time zone?
Time-zone abbreviations were never standardised: several countries independently picked the same letters. AST is one of the worst offenders, with 2 meanings in current use. This is why calendar software and databases use IANA identifiers like America/Halifax instead: they are unique, and they carry the daylight-saving rules with them.
Is AST in use right now?
Not at this moment. Atlantic Standard Time is currently on ADT (UTC-3) because of daylight saving. AST comes back when the clocks change: see the date below.