AST Time Now — Atlantic Standard Time
The current AST time (Atlantic Standard Time, UTC -04:00) is shown below.
AST — UTC -04:00
Thursday, 22 October 2026 AST
The clock always shows AST (UTC -04:00). Places in this zone switch between standard and daylight time during the year, so their local time can differ from AST by an hour.
Where AST is used
In 2026, 29 zones in the tz database show AST : 23 all year and 6 only part of the year, switching to ADT for the rest . The all-year zones are the ones that don't observe daylight saving: Anguilla, Antigua & Barbuda, Aruba, Barbados, Canada, Curaçao, Dominica, Grenada.
| Zone | Country | January | July |
|---|---|---|---|
| America/Anguilla | Anguilla | AST -04:00 | AST -04:00 |
| America/Antigua | Antigua & Barbuda | AST -04:00 | AST -04:00 |
| America/Aruba | Aruba | AST -04:00 | AST -04:00 |
| America/Barbados | Barbados | AST -04:00 | AST -04:00 |
| America/Blanc-Sablon | Canada | AST -04:00 | AST -04:00 |
| America/Curacao | Curaçao | AST -04:00 | AST -04:00 |
| America/Dominica | Dominica | AST -04:00 | AST -04:00 |
| America/Glace Bay | Canada | AST -04:00 | ADT -03:00 |
| America/Goose Bay | Canada | AST -04:00 | ADT -03:00 |
| America/Grenada | Grenada | AST -04:00 | AST -04:00 |
| America/Guadeloupe | Guadeloupe | AST -04:00 | AST -04:00 |
| America/Halifax | Canada | AST -04:00 | ADT -03:00 |
| America/Kralendijk | Caribbean Netherlands | AST -04:00 | AST -04:00 |
| America/Lower Princes | Sint Maarten | AST -04:00 | AST -04:00 |
| America/Marigot | St. Martin | AST -04:00 | AST -04:00 |
| America/Martinique | Martinique | AST -04:00 | AST -04:00 |
| America/Moncton | Canada | AST -04:00 | ADT -03:00 |
| America/Montserrat | Montserrat | AST -04:00 | AST -04:00 |
| America/Port of Spain | Trinidad & Tobago | AST -04:00 | AST -04:00 |
| America/Puerto Rico | Puerto Rico | AST -04:00 | AST -04:00 |
| America/Santo Domingo | Dominican Republic | AST -04:00 | AST -04:00 |
| America/St Barthelemy | St. Barthélemy | AST -04:00 | AST -04:00 |
| America/St Kitts | St. Kitts & Nevis | AST -04:00 | AST -04:00 |
| America/St Lucia | St. Lucia | AST -04:00 | AST -04:00 |
| America/St Thomas | U.S. Virgin Islands | AST -04:00 | AST -04:00 |
| America/St Vincent | St. Vincent & Grenadines | AST -04:00 | AST -04:00 |
| America/Thule | Greenland | AST -04:00 | ADT -03:00 |
| America/Tortola | British Virgin Islands | AST -04:00 | AST -04:00 |
| Atlantic/Bermuda | Bermuda | AST -04:00 | ADT -03:00 |
About AST
Offset & DST
UTC offset: -04:00
Daylight saving: Observed
Daylight-time counterpart: ADT (UTC -03:00)
Representative IANA zone: America/Halifax
IANA zones at AST
Converting AST to other time zones
AST is fixed at UTC -04:00 — written -0400 in email headers and -04:00 in ISO 8601 timestamps. In 2026, Halifax is on AST until 8 March and from 1 November to the end of the year. The table below uses each abbreviation's own fixed offset; for a specific place, check its city page, since local clocks switch between standard and daylight abbreviations.
| Zone | Difference | When it's 12:00 AST | Converter |
|---|---|---|---|
| UTC Coordinated Universal Time | +4 h | 16:00 | Hour by hour → |
| PST Pacific Standard Time | −4 h | 08:00 | Hour by hour → |
| MST Mountain Standard Time | −3 h | 09:00 | Hour by hour → |
| CST Central Standard Time | −2 h | 10:00 | Hour by hour → |
| EST Eastern Standard Time | −1 h | 11:00 | Hour by hour → |
| BRT Brasília Time | +1 h | 13:00 | Hour by hour → |
| BST British Summer Time | +5 h | 17:00 | Hour by hour → |
| CET Central European Time | +5 h | 17:00 | Hour by hour → |
| EET Eastern European Time | +6 h | 18:00 | Hour by hour → |
| MSK Moscow Standard Time | +7 h | 19:00 | Hour by hour → |
| GST Gulf Standard Time | +8 h | 20:00 | Hour by hour → |
| IST India Standard Time | +9:30 h | 21:30 | Hour by hour → |
| CST China Standard Time | +12 h | 00:00 (+1 day) | Hour by hour → |
| JST Japan Standard Time | +13 h | 01:00 (+1 day) | Hour by hour → |
| AEST Australian Eastern Standard Time | +14 h | 02:00 (+1 day) | Hour by hour → |
AST can mean something else
Time zone abbreviations are not unique. Besides Atlantic Standard Time, AST is also used for:
- Arabia Standard Time (UTC +03:00) — Saudi Arabia, Iraq, Kuwait, Qatar and Bahrain
When the difference matters — meeting invites, software, contracts — write the UTC offset (UTC -04:00) or an IANA zone name such as America/Halifax instead.
Countries commonly using AST
Other zones at UTC -04:00
AST questions
- What is AST in UTC?
- AST (Atlantic Standard Time) is UTC -04:00. In ISO 8601 timestamps it is written -04:00, in email and HTTP headers -0400.
- Is AST the same as ADT?
- No. AST is UTC -04:00; ADT is UTC -03:00, the daylight-saving time the same places use for the other part of the year. In 2026, Halifax is on AST until 8 March and from 1 November to the end of the year.
- Which countries use AST?
- In 2026, zones showing AST are found in Anguilla, Antigua & Barbuda, Aruba, Barbados, Bermuda, British Virgin Islands, Canada, Caribbean Netherlands, Curaçao, Dominica, Dominican Republic, Greenland, Grenada, Guadeloupe, Martinique, Montserrat, Puerto Rico, Sint Maarten, St. Barthélemy, St. Kitts & Nevis and 5 more.
- Does AST mean anything else?
- Yes. AST is also used for Arabia Standard Time (UTC +03:00). Use a UTC offset or an IANA zone name when it matters.
More tools for AST
Look up the exact IANA zone behind AST, see it on the offset map, or compare it against other cities.