Also known as: Atlantic Time (AT) and Atlantic Standard Time (AST)
Areas with same time currently (UTC -3).
Currently has same time zone offset as ADT (UTC -3) but different time zone name.
Atlantic Daylight Time (ADT) is 3 hours behind Coordinated Universal Time (UTC). This time zone is a Daylight Saving Time time zone and is used in: North America, Atlantic.
What Is Atlantic Daylight Time?
Atlantic Daylight Time (ADT) is an eastern time zone in North America. It is used in the northeast of Canada.
It covers all or parts of four provinces in Canada but is not used in mainland United States or its US territories.
In North America, Atlantic Daylight Time shares a border with Eastern Daylight Time (EDT) in the west.
ADT or AST?
Atlantic Daylight Time (ADT) is a North American time zone in use from the second Sunday in March to the first Sunday in November during Daylight Saving Time (DST). Atlantic Standard Time (AST) is used during the remainder of the year.
ADT Is the Atlantic Time Zone
In everyday usage, ADT is often referred to as Atlantic Time (AT) or the Atlantic Time Zone. This can add a bit of confusion as the term Atlantic Time does not differentiate between standard time and Daylight Saving Time, so Atlantic Time switches between AST and ADT in areas that use DST during part of the year.
Most North American time zones have generic terms, including Pacific Time (PT), Mountain Time (MT), Central Time (CT), and Eastern Time (ET).
Converting Atlantic Daylight Time to Other US Time Zones
- Atlantic Daylight Time (ADT) is 1 hour ahead of Eastern Daylight Time (EDT).
To convert ADT to EDT, you have to subtract one hour. - Atlantic Daylight Time (ADT) is 2 hours ahead of Central Daylight Time (CDT).
To convert ADT to CDT, you have to subtract two hours. - Atlantic Daylight Time (ADT) is 3 hours ahead of Mountain Daylight Time (MDT).
To convert ADT to MDT, you have to subtract three hours. - Atlantic Daylight Time (ADT) is 4 hours ahead of Pacific Daylight Time (PDT).
To convert ADT to PDT, you have to subtract four hours.
Time Zone Converter: UTC to ADT
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:
Atlantic
Other Time Zones in UTC -3
Some time zones exist that have the same offset as ADT, but can be found under a different name:
- AMST – Amazon Summer Time
- ART – Argentina Time
- BRT – Brasília Time
- CLST – Chile Summer Time
- FKST – Falkland Islands Summer Time
- GFT – French Guiana Time
- P – Papa Time Zone
- PMST – Pierre & Miquelon Standard Time
- PYST – Paraguay Summer Time
- ROTT – Rothera Time
- SRT – Suriname Time
- UYT – Uruguay Time
- WARST – Western Argentine Summer Time
- WGT – West Greenland Time