Atlantic Standard Time (AST)
AST is UTC-4. Current Atlantic Time (Canada) and when AST applies.
Atlantic Time (Canada) now
--:--:--
Tuesday, November 3, 2026
ASTUTC-4
Atlantic Time is on AST right now
Exact AST (UTC-4) time now: --:--:--
About AST
- Full Name
- Atlantic Standard Time
- Abbreviation
- AST
- UTC Offset
- UTC-4
- Atlantic Time is on
- Standard Time (AST)
- Daylight Saving Time
- Atlantic Time: Starts Mar 14, 2027 · switches between AST and ADT
Atlantic Standard Time (AST) is UTC-4, one hour ahead of Eastern Time. Atlantic Canada and Bermuda use AST in winter and Atlantic Daylight Time (ADT, UTC-3) in summer, while Puerto Rico and most of the Caribbean stay on AST all year.
Where AST is used
Switches between AST and ADT
- Nova Scotia, New Brunswick and Prince Edward Island, Canada (Halifax, Moncton)
- Bermuda
AST all year (no DST)
- Puerto Rico, the Dominican Republic, Barbados, Trinidad and Tobago, and Martinique
Not to be confused with: Arabia Standard Time (Saudi Arabia, Iraq, Kuwait) (UTC+3).
Major Cities in Atlantic Time and AST
Each city shows its own current abbreviation, so places on daylight saving time are labelled accordingly.
AST vs Other Time Zones
| Comparison | By definition | Right now (local clocks) |
|---|---|---|
| AST to ADT | +1 hour | Same region |
| AST to EST | -1 hour | -1 hour |
| AST to NST | +30 minutes | +30 minutes |
| AST to UTC | +4 hours | +4 hours |
“By definition” compares the fixed offsets of the abbreviations. “Right now” compares the actual local time in each region today, including daylight saving time.
AST FAQs
What is AST?
Atlantic Standard Time (AST) is UTC-4, one hour ahead of Eastern Time. Atlantic Canada and Bermuda use AST in winter and Atlantic Daylight Time (ADT, UTC-3) in summer, while Puerto Rico and most of the Caribbean stay on AST all year.
What is the UTC offset of AST?
AST is always UTC-4. When Atlantic Time observes daylight saving time, it uses ADT (UTC-3) instead.
Is it AST or ADT right now?
Atlantic Time is on AST right now. AST is UTC-4. Atlantic Time switches to ADT (UTC-3) on Sunday, March 14, 2027 at 2:00 AM.
When does Atlantic Time switch between AST and ADT?
In 2026, Atlantic Time switches to ADT on Sunday, March 8, 2026 at 2:00 AM (clocks go forward 1 hour) and back on Sunday, November 1, 2026 at 2:00 AM (clocks go back 1 hour).
Where is AST used all year?
These places use UTC-4 all year without daylight saving time: Puerto Rico, the Dominican Republic, Barbados, Trinidad and Tobago, and Martinique.
Does AST have other meanings?
Yes. AST can also mean Arabia Standard Time (Saudi Arabia, Iraq, Kuwait) (UTC+3). This page covers Atlantic Standard Time (UTC-4). When sharing a time, adding the UTC offset avoids confusion.