ADT/AST
Atlantic Daylight Time
GMT -3
AST automatically adjusted to ADT time zone, that is in use
GMT
Greenwich Mean Time
GMT +0

Time Difference

Atlantic Daylight Time is 3 hours behind Greenwich Mean Time
12:30 pm12:30 in ADT is 3:30 pm15:30 in GMT

AST to GMT call time
Best time for a conference call or a meeting is between 8am-2pm in AST which corresponds to 12pm-6pm in GMT

12:30 pm12:30 Atlantic Daylight Time (ADT). Offset UTC -3:00 hours
3:30 pm15:30 Greenwich Mean Time (GMT). Offset UTC 0:00 hours

12:30 pm12:30 ADT / 3:30 pm15:30 GMT

ADT GMT
12am (midnight) 3am
1am 4am
2am 5am
3am 6am
4am 7am
5am 8am
6am 9am
7am 10am
8am 11am
9am 12pm (noon)
10am 1pm
11am 2pm
12pm (noon) 3pm
1pm 4pm
2pm 5pm
3pm 6pm
4pm 7pm
5pm 8pm
6pm 9pm
7pm 10pm
8pm 11pm
9pm 12am (midnight)
10pm 1am
11pm 2am
0:00 3:00
1:00 4:00
2:00 5:00
3:00 6:00
4:00 7:00
5:00 8:00
6:00 9:00
7:00 10:00
8:00 11:00
9:00 12:00
10:00 13:00
11:00 14:00
12:00 15:00
13:00 16:00
14:00 17:00
15:00 18:00
16:00 19:00
17:00 20:00
18:00 21:00
19:00 22:00
20:00 23:00
21:00 0:00
22:00 1:00
23:00 2:00

Atlantic Standard Time

Offset: AST is 4 hours behind Greenwich Mean Time (GMT) and is used in North America

Countries: It is used in following countries: Antigua & Barbuda, Anguilla, Aruba, Barbados, St Barthelemy, Bermuda, Caribbean NL, Canada, Curaçao, Dominica, Dominican Republic, Grenada, Greenland, Guadeloupe, St Kitts & Nevis, St Lucia, St Martin (French), Martinique, Montserrat, Puerto Rico, St Maarten (Dutch), Trinidad & Tobago, St Vincent, Virgin Islands (UK), Virgin Islands (US)

Principal Cities: The largest city in the AST timezone is Santo Domingo from Dominican Republic with population about 2.202 million people. Other major cities in the area are Santiago de los Caballeros, Santo Domingo Oeste, San Juan, Halifax

French: HNA - Heure Normale de l'Atlantique

Spanish: AST - Tiempo Estándar del Atlántico

AST Time Zone Geo Map
AST timezone map

Daylight Saving: This is a standard time zone, however during summer some places switch clocks for one hour forward when daylight saving comes into effect and observe Atlantic Daylight Time (ADT).

Daylight saving time clock moves forward for one hour from 2am to 3amEnd: Atlantic Standard Time (AST) has ended on Sunday, March 10, 2024 at 2:00 am local time and clocks were set one hour forward to Sunday, March 10, 2024, 3:00 am local daylight time instead. Standard time ends annually the on second Sunday of March.

Daylight saving time clock moves back for one hour from 2am to 1amStart: Atlantic Standard Time (AST) starts on Sunday, November 3, 2024 at 2:00 am local time and clocks are set one hour back to Sunday, November 3, 2024, 1:00 am. Standard time starts annually the on first Sunday of November.

AST representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • -04 - basic short
  • -0400 - basic
  • -04:00 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • -0400 - sign character (-) followed by a four digit time providing hours (04) and minutes (00) of the offset. Indicates four hour and zero minutes time differences to the west of the zero meridian.
Military/NATO: Used by the U.S. military, Chinese military and others
  • Quebec - Military abbreviation for AST
  • Q - short form of 'Quebec'
IANA/Olson: Reflects AST time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • America/Anguilla
  • America/Antigua
  • America/Aruba
  • America/Barbados
  • America/Blanc-Sablon
  • America/Curacao
  • America/Dominica
  • America/Glace_Bay
  • America/Goose_Bay
  • America/Grenada
  • America/Guadeloupe
  • America/Halifax
  • America/Kralendijk
  • America/Lower_Princes
  • America/Marigot
  • America/Martinique
  • America/Moncton
  • America/Montserrat
  • America/Port_of_Spain
  • America/Puerto_Rico
  • America/Santo_Domingo
  • America/St_Barthelemy
  • America/St_Kitts
  • America/St_Lucia
  • America/St_Thomas
  • America/St_Vincent
  • America/Thule
  • America/Tortola
  • America/Virgin
  • Atlantic/Bermuda
  • Canada/Atlantic
AST Abbreviation: Several time zones share AST abbreviation and it could refer to these time zones
  • Atlantic Standard Time - UTC -4
  • Arabia Standard Time - UTC +3
  • Arabian Standard Time - UTC +3
  • Acre Standard Time - UTC -5
  • Azores Standard Time - UTC -1
  • Apia Standard Time - UTC +13
Time zones with the GMT -4 offset:
  • AST - Atlantic Standard Time
  • EDT - Eastern Daylight Time
  • AMT - Amazon Time
  • BOT - Bolivia Time
  • CDT - Cuba Daylight Time
  • CLT - Chile Standard Time
  • FKT - Falkland Island Time
  • GYT - Guyana Time
  • HLV - Hora Legal de Venezuela
  • PYT - Paraguay Time
  • Q - Quebec Time Zone
  • VET - Venezuelan Standard Time

Greenwich Mean Time

Offset: GMT is 0 hours ahead Greenwich Mean Time (GMT) and is used in Europe

Countries: It is used in following countries: Burkina Faso, Côte d'Ivoire, Britain (UK), Guernsey, Ghana, Greenland, Gambia, Guinea, Guinea-Bissau, Ireland, Isle of Man, Iceland, Jersey, Liberia, Mali, Mauritania, St Helena, Sierra Leone, Senegal, Sao Tome & Principe, Togo

Principal Cities: The largest city in the GMT timezone is London from United Kingdom with population about 7.557 million people. Other major cities in the area are Abidjan, Dakar, Grand Dakar, Accra

Greenwich Mean Time (GMT) originally referred to the mean solar time at the Royal Observatory in Greenwich, London. It is now often used to refer to Coordinated Universal Time (UTC) when this is viewed as a time zone, and in casual use for the most parts it is the same. In military GMT is known as Zulu time.Greenwich Mean Time was the same as Universal Time (UT), until the introduction of UTC in 1972 a standard astronomical concept used in many technical fields.

GMT Time Zone Geo Map
GMT timezone map

GMT representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • Z - is the zone designator for the zero UTC/GMT offset, also known as 'Zulu' time
  • +00 - basic short
  • +0000 - basic
  • +00:00 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • +0000 - sign character (+) followed by a four digit time providing hours (00) and minutes (00) of the offset. Indicates zero hour and zero minutes time differences of the zero meridian.
Military/NATO: Used by the U.S. military, Chinese military and others
  • Zulu - Military abbreviation for GMT
  • Z - short form of 'Zulu'
IANA/Olson: Reflects GMT time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • Africa/Abidjan
  • Africa/Accra
  • Africa/Bamako
  • Africa/Banjul
  • Africa/Bissau
  • Africa/Conakry
  • Africa/Dakar
  • Africa/Freetown
  • Africa/Lome
  • Africa/Monrovia
  • Africa/Nouakchott
  • Africa/Ouagadougou
  • Africa/Sao_Tome
  • Africa/Timbuktu
  • America/Danmarkshavn
  • Atlantic/Reykjavik
  • Atlantic/St_Helena
  • Eire
  • Etc/GMT
  • Etc/GMT+0
  • Etc/GMT-0
  • Etc/GMT0
  • Etc/Greenwich
  • Europe/Belfast
  • Europe/Dublin
  • Europe/Guernsey
  • Europe/Isle_of_Man
  • Europe/Jersey
  • Europe/London
  • GB
  • GB-Eire
  • GMT
  • GMT+0
  • GMT-0
  • GMT0
  • Greenwich
  • Iceland
GMT Abbreviation: Several time zones share GMT abbreviation and it could refer to these time zones
  • Greenwich Mean Time - UTC +0
  • GMT+03:00 - UTC +3
  • GMT+06:00 - UTC +6
  • GMT - UTC +0
  • GMT+11:00 - UTC +11
Time zones with the GMT +0 offset:
  • EGST - Eastern Greenland Summer Time
  • GMT - Greenwich Mean Time
  • WET - Western European Time
  • AZOST - Azores Summer Time
  • UTC - Universal Time Coordinated
  • WT - Western Sahara Standard Time
  • Z - Zulu Time Zone