Home > Time Zones > Abbreviations > ADT – Atlantic Daylight Time

ADT – Atlantic Daylight Time / Atlantic Daylight Saving Time (Daylight Saving Time)

Also known as: ADST – Atlantic Daylight Saving Time, AST – Atlantic Summer Time

Atlantic Daylight Time Note:

North America, Atlantic Ocean: ADT is currently not observed since DST isn't active. Locations are currently observing AST instead.

Time zone map of ADT
No locations currently on ADT.
Observes ADT part of the year.
Areas with same time currently (UTC -3:00).
No locations are currently on ADT – Atlantic Daylight Time.
Observes ADT – Atlantic Daylight Time part of the year, but not currently.
Currently has same time zone offset as ADT (UTC -3:00) but different time zone name.

Atlantic Daylight Time (ADT) is 3 hours behind Coordinated Universal Time (UTC). This time zone is a DST (daylight saving time) time zone and is used in: North America, Atlantic Ocean.

This time zone is often called ADT Time Zone.

See full time zone map

Winter Time & DST

This time zone is a daylight saving/summer time zone, in the winter some places will switch to the corresponding standard time zone: AST (Atlantic Standard Time).

Email time zone indicator: -0300

An email sent from someone in the Atlantic Daylight Time (ADT) time zone will have the time zone listed as "-0300" in the headers of the email. (However, "-0300" does not have to be in Atlantic Daylight Time, as other time zones could have the same UTC offset).

Where and when is ADT observed?

North America

Canadian provinces using ADT in the summer and AST in the winter

  • Most of Labrador (mainland part of the province of Newfoundland and Labrador)
  • New Brunswick
  • Nova Scotia
  • Prince Edward Island

Areas of Greenland using ADT in the summer and AST in the winter

  • Thule area

Atlantic Ocean

Atlantic islands/territories using ADT in the summer and AST in the winter

  • Bermuda

No locations currently on ADT

  • UTC Offset: UTC -3:00

Find current time and time zone by city


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Other names

HAA – Heure Avancée de l'Atlantique (French)

Other time zones named ADT

ADT – Arabia Daylight Time

Example cities

Canada – Halifax (Summer)
Bermuda – Hamilton (Summer)

Related time zones

AST – Atlantic Standard Time (Standard Time)


Time Zone Map with DST

Time Zone Map

Time Zone Map