PDT/PST
Pacific Daylight Time
GMT -7
PST automatically adjusted to PDT time zone, that is in use
ADT/AST
Atlantic Daylight Time
GMT -3
AST automatically adjusted to ADT time zone, that is in use

Time Difference

Pacific Daylight Time is 4 hours behind of Atlantic Daylight Time
So 9:30 am09:30 in PDT is 1:30 pm13:30 in ADT

9:30 am09:30 Pacific Daylight Time (PDT). Offset UTC -7:00 hours
1:30 pm13:30 Atlantic Daylight Time (ADT). Offset UTC -3:00 hours

9:30 am09:30 PDT / 1:30 pm13:30 ADT

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

Pacific Standard Time

Offset: PST is 8 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 PST 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: This is a standard timezone, however during summer some places adjust time for one hour forward for daylight saving and observe Pacific Daylight Time (PDT).

End: PST ended and clocks were set one hour forward on Sunday, 08 March 2020, at 2:00 (2:00 am) local time.

Start: PST starts and clocks are set one hour back on Sunday, 01 November 2020, at 2:00 (2:00 am) local time.

French: HNP - Heure Normale du Pacifique

Spanish: PT - Tiempo del Pacífico, PT - Zona Noroeste

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

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • -08 - basic short
  • -0800 - basic
  • -08:00 - extended

Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • -0800 - sign character (-) followed by a four digit time providing hours (08) and minutes (00) of the offset. Indicates eight 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
  • Uniform - Military abbreviation for PST
  • U - short form of 'Uniform'

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

PST Abbreviation: Several time zones share PST abbreviation and it could refer to these time zones

  • Pacific Standard Time - UTC -8
  • Pitcairn Standard Time - UTC -8

Time zones with the GMT -8 offset:

  • AKDT - Alaska Daylight Time
  • PST - Pacific Standard Time
  • PT - Pacific Time
  • YDT - Yukon Daylight Time
  • PST - Pitcairn Standard Time
  • U - Uniform 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 ended and clocks were set one hour forward on Sunday, 08 March 2020, at 2:00 (2:00 am) local time.

Start: AST starts and clocks are set one hour back on Sunday, 01 November 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 -