North American time zones:

Time zone offset: UTC - 3 hours

Note that ADT is a daylight saving time/summer time zone. It is generally only used during the summer in the places listed below, during the winter AST is used instead

Time zone abbreviations: ADT, HAA

Full name is Atlantic Daylight Time
HAA – Heure Avancée de l'Atlantique (French)

Email time zone indicator: -0300

An email sent from someone in the 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 ADT, as other time zones could have the same UTC offset).

Where and when is ADT observed?

ADT is used during summer in these Canadian provinces (AST during winter)

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

Example location in ADT

• Halifax - during summer

Other time zones in North America

• NST - Newfoundland Standard Time
• NDT - Newfoundland Daylight Time
• AST - Atlantic Standard Time
• EST - Eastern Standard Time
• EDT - Eastern Daylight Time
• CST - Central Standard Time
• CDT - Central Daylight Time
• MST - Mountain Standard Time
• MDT - Mountain Daylight Time
• PST - Pacific Standard Time
• PDT - Pacific Daylight Time
• AKST - Alaska Standard Time
• AKDT - Alaska Daylight Time
• HAST - Hawaii-Aleutian Standard Time
• HADT - Hawaii-Aleutian Daylight Time