AST/ADT Atlantic Time Zone

Standard time and daylight time is observed by this time zone; AST Atlantic Standard Time is 4 hours behind of UTC/GMT time and ADT Atlantic Daylight Time is behind by 3 hours.

Atlantic Standard Time:
Wednesday December 12th 9:12am AST
Status: Time Zone: UTC/GMT Offset:
Being Observed
AST -04:00
Atlantic Daylight Time:
Wednesday December 12th 10:12am ADT
Status: Time Zone: UTC/GMT Offset:
Not Being Observed ADT -03:00
Year: ADT Begins: ADT Ends:
2020 Sunday March 8th Sunday November 1st
2019 Sunday March 10th Sunday November 3rd
2018 Sunday March 11th Sunday November 4th
2017 Sunday March 12th Sunday November 5th
2016 Sunday March 13th Sunday November 6th

Countries which observe the AST/ADT time zone:


  • Canada*
  • Greenland*


  • Bermuda

(*) indicates that the time zone is only observed in certain areas of the country. No asterisk indicates that the entire country observes this time zone.

Areas in Canada which observe the Atlantic Time Zone

Majority of Labrador from Cartwright north and west observes AST during the winter and ADT during the summer and the south-eastern tip near Newfoundland observes the Newfoundland Time Zone. New Brunswick, Nova Scotia and Prince Edward Island observe only AST.

Areas in Greenland which observe the Atlantic Time Zone

  • Thule Air Base (IATA THU)
Atlantic Time Zone Identifiers:
(BM) Atlantic/Bermuda(CA) America/Glace_Bay
(CA) America/Goose_Bay(CA) America/Halifax
(CA) America/Moncton(GL) America/Thule
« List of World Time Zones