What Is Atlantic Daylight Time?
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.
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.
Where and When is ADT Observed?
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:
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
Time zones by continent/region
- Central America
- Indian Ocean
- North America
- South America