PDT
Pacific Daylight Time
GMT -7
AST
Atlantic Standard Time
GMT -4
AST is NOT in use by many locations
ADT (Atlantic Daylight Time) is used instead. Switch to ADT time zone or select one of the cities Santo Domingo, Santiago de los Caballeros, Santo Domingo Oeste for automatic timezone change.

Time Difference

Pacific Daylight Time is 3 hours behind of Atlantic Standard Time
So 7:00 am07:00 in PDT is 10:00 am10:00 in AST

7:00 am07:00 Pacific Daylight Time (PDT). Offset UTC -7:00 hours
10:00 am10:00 Atlantic Standard Time (AST). Offset UTC -4:00 hours

7:00 am07:00 PDT / 10:00 am10:00 AST

PDT AST
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

Pacific Daylight Time

Offset: PDT is 7 hours behind Greenwich Mean Time (GMT) and is used in North America

Countries: It is used in following countries: Canada, Mexico, United States

Principal Cities: The largest city in the PDT timezone is Los Angeles from USA with population about 3.793 million people. Other major cities in the area are Vancouver, Tijuana, San Diego, San Jose

Daylight Saving: Pacific Daylight Time (PDT) is a daylight saving/summer timezone, however during winter some places switch clocks for one hour back and observe Pacific Standard Time (PST).

Start: Pacific Daylight Time (PDT) starts annually on the same date and time. and clocks were set one hour forward on Sunday, March 8, 2020, at 2:00 (2:00 am) local time.

End: Pacific Daylight Time (PDT) ends annually on the same date and time. and clocks are set one hour back on Sunday, November 1, 2020, at 2:00 (2:00 am) local time.

French: HAP - Heure Avancée du Pacifique

Spanish: PT - Zona Noroeste

PDT Time Zone Geo Map
PDT timezone map
PDT representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • -07 - basic short
  • -0700 - basic
  • -07:00 - extended

Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • -0700 - sign character (-) followed by a four digit time providing hours (07) and minutes (00) of the offset. Indicates seven 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
  • Tango - Military abbreviation for PDT
  • T - short form of 'Tango'

IANA/Olson: Reflects PDT time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • America/Dawson
  • America/Ensenada
  • America/Los_Angeles
  • America/Santa_Isabel
  • America/Tijuana
  • America/Vancouver
  • America/Whitehorse
  • Canada/Pacific
  • Canada/Yukon
  • Mexico/BajaNorte
  • PST8PDT
  • US/Pacific
  • US/Pacific-New

Time zones with the GMT -7 offset:

  • MST - Mountain Standard Time
  • PDT - Pacific Daylight Time
  • T - Tango Time Zone


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

Daylight Saving: This is a standard timezone, however during summer some places adjust time for one hour forward for daylight saving and observe Atlantic Daylight Time (ADT).

End: AST ends annually on the same date and time. and clocks were set one hour forward on Sunday, March 8, 2020, at 2:00 (2:00 am) local time.

Start: AST starts annually on the same date and time. and clocks are set one hour back on Sunday, November 1, 2020, at 2:00 (2:00 am) local time.

French: HNA - Heure Normale de l'Atlantique

Spanish: AST - Tiempo Estándar del Atlántico

AST Time Zone Geo Map
AST timezone map
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

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
  • PYT - Paraguay Time
  • Q - Quebec Time Zone
  • VET - Venezuelan Standard Time
  • -04 -