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Atlantic Daylight Time, Atlantic Standard Time, ADT, AST

From mid-March to early November, Atlantic Daylight Time is observed in the Maritime provinces and parts of Quebec and Labrador. From early November to mid-March, Atlantic Standard Time is in effect.

  • Remember to set your watch to Atlantic Standard Time when crossing the Quebec–New Brunswick border.


Usage is divided with regard to the use of capitals in the names of time zones. However, Canadian dictionaries and most Canadian style guides treat the official names of time zones as proper nouns and capitalize all words: Atlantic Daylight Time and Atlantic Standard Time.


The name of the time zone is abbreviated when a specific time is stated; otherwise, it is written out in full. The abbreviations ADT and AST are written in upper case, with no periods.

Time zones may be stated with either the 12-hour or the 24-hour system (e.g. 3:25 p.m. ADT or 15:25 ADT).

  • The historical interpreters at Louisbourg are on duty from 9:30 a.m. to 5:30 p.m. ADT.
  • The sun will rise over Souris, P.E.I., at 06:47 AST tomorrow.