Atlantic Time Zone

Time Zone of a Place
Time zone of

What is the Atlantic Time Zone?

Answer

Atlantic Time Zone
UTC−4 (AST) and UTC−3 (ADT)

The same offset as a plain number: UTC−4.

Time Zone Facts

Abbreviations
AST / ADT
Standard time
UTC−4
Daylight saving time
UTC−3
Clock changes
daylight time from March 8, 2026 and standard time from November 1, 2026
Daylight saving time in effect now
Yes

Where This Zone Applies

The clocks do not change everywhere in this zone. On standard time all year: Puerto Rico.
PlaceStandard timeClock changes
Canada — the Maritimes — Nova Scotia, New Brunswick, Prince Edward Island and most of LabradorUTC−4Yes
Newfoundland and Labrador — most of Labrador, including Happy Valley-Goose Bay and Labrador CityUTC−4Yes
Nova ScotiaUTC−4Yes
Puerto RicoUTC−4No
HalifaxUTC−4Yes

Time Difference

UTC
3 hours behind
Eastern Time
1 hour ahead
Central Time
2 hours ahead
Mountain Time
3 hours ahead
Pacific Time
4 hours ahead
Moscow Time
MSK−7 in standard time, MSK−6 in daylight time

Current time in the zone

UTC−3 — subtract 3 hours from UTC

Related Calculations

See Also

Time Zone of a Place

This reference shows what time zone a place is in: the name of the zone and its abbreviations, the UTC offset in standard and daylight time, whether the clocks change there and when, plus the difference from UTC, from the four US zones and from Moscow. For example, it can help you find out what is the Atlantic Time Zone? (The answer is: UTC−4 (AST) and UTC−3 (ADT)). Pick a place or a zone (e.g. 'Atlantic Time') and hit the 'Find out' button.
Time Zone of a Place
Time zone of

Named Time Zones

Time zoneStandard timeDaylight saving time
Alaska TimeUTC−9UTC−8
Atlantic TimeUTC−4UTC−3
Australian Central TimeUTC+9:30UTC+10:30
Australian Eastern TimeUTC+10UTC+11
Australian Western TimeUTC+8not observed
Brasília TimeUTC−3not observed
Central European TimeUTC+1UTC+2
Central TimeUTC−6UTC−5
Chamorro TimeUTC+10not observed
East Africa TimeUTC+3not observed
Eastern European TimeUTC+2UTC+3
Eastern TimeUTC−5UTC−4
Greenwich Mean TimeUTCUTC+1
Hawaii–Aleutian TimeUTC−10not observed
Hong Kong TimeUTC+8not observed
India Standard TimeUTC+5:30not observed
Irish TimeUTCUTC+1
Irkutsk TimeUTC+8not observed
Israel TimeUTC+2UTC+3
Japan Standard TimeUTC+9not observed
Kaliningrad TimeUTC+2not observed
Kamchatka TimeUTC+12not observed
Korea Standard TimeUTC+9not observed
Krasnoyarsk TimeUTC+7not observed
Magadan TimeUTC+11not observed
Mexican Central TimeUTC−6not observed
Mexican Northwest TimeUTC−8UTC−7
Mexican Pacific TimeUTC−7not observed
Mexican Southeast TimeUTC−5not observed
Moscow TimeUTC+3not observed
Mountain TimeUTC−7UTC−6
Newfoundland TimeUTC−3:30UTC−2:30
New Zealand TimeUTC+12UTC+13
Omsk TimeUTC+6not observed
Pacific TimeUTC−8UTC−7
Samara TimeUTC+4not observed
Samoa TimeUTC−11not observed
South Africa Standard TimeUTC+2not observed
Vladivostok TimeUTC+10not observed
Western European TimeUTCUTC+1

FAQ

What is the Atlantic Time Zone?

Atlantic Time Zone UTC−4 (AST) and UTC−3 (ADT)

Where does the Atlantic Time Zone apply?

Among the places in this reference: Nova Scotia, Puerto Rico and Halifax.

Do the clocks change in the Atlantic Time Zone?

Yes: UTC−4 in standard time and UTC−3 in daylight time. The clocks do not change everywhere in this zone. On standard time all year: Puerto Rico.

What does AST stand for?

AST is the standard time of the zone (UTC−4), and ADT its daylight time (UTC−3).

See Also