CDT/CST
Central Daylight Time
GMT -5
CST automatically adjusted to CDT time zone, that is in use
AST
Atlantic Standard Time
GMT -4

Time Difference

Central Daylight Time is 1 hours behind Atlantic Standard Time
11:30 pm23:30 in CDT is 12:30 am00:30 in AST

CST to AST call time
Best time for a conference call or a meeting is between 8am-4pm in CST which corresponds to 10am-6pm in AST

11:30 pm23:30 Central Daylight Time (CDT). Offset UTC -5:00 hours
12:30 am00:30 Atlantic Standard Time (AST). Offset UTC -4:00 hours

11:30 pm23:30 CDT / 12:30 am00:30 AST

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

Central Standard Time

Offset: CST is 6 hours behind Greenwich Mean Time (GMT) and is used in North America

Countries: It is used in following countries: Belize, Canada, Costa Rica, Guatemala, Honduras, Mexico, Nicaragua, El Salvador, United States

Principal Cities: The largest city in the CST timezone is Mexico City from Mexico with population about 12.294 million people. Other major cities in the area are Chicago, Houston, Iztapalapa, Ecatepec

French: HNC - Heure Normale du Centre

Spanish: CT - Tiempo Central Estándar, CT - Zona Centro

CST Time Zone Geo Map
CST 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 Central Daylight Time (CDT).

Daylight saving time clock moves forward for one hour from 2am to 3amEnd: Central Standard Time (CST) 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: Central Standard Time (CST) 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.

CST representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • -06 - basic short
  • -0600 - basic
  • -06:00 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • -0600 - sign character (-) followed by a four digit time providing hours (06) and minutes (00) of the offset. Indicates six 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
  • Sierra - Military abbreviation for CST
  • S - short form of 'Sierra'
IANA/Olson: Reflects CST time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • America/Bahia_Banderas
  • America/Belize
  • America/Chicago
  • America/Costa_Rica
  • America/El_Salvador
  • America/Guatemala
  • America/Indiana/Knox
  • America/Indiana/Tell_City
  • America/Knox_IN
  • America/Managua
  • America/Matamoros
  • America/Menominee
  • America/Merida
  • America/Mexico_City
  • America/Monterrey
  • America/North_Dakota/Beulah
  • America/North_Dakota/Center
  • America/North_Dakota/New_Salem
  • America/Rainy_River
  • America/Rankin_Inlet
  • America/Regina
  • America/Resolute
  • America/Swift_Current
  • America/Tegucigalpa
  • America/Winnipeg
  • CST6CDT
  • Canada/Central
  • Canada/Saskatchewan
  • Mexico/General
  • US/Central
  • US/Indiana-Starke
CST Abbreviation: Several time zones share CST abbreviation and it could refer to these time zones
  • Central Standard Time - UTC -6
  • China Standard Time - UTC +8
  • Cuba Standard Time - UTC -5
  • Colombia Standard Time - UTC -5
Time zones with the GMT -6 offset:
  • CST - Central Standard Time
  • CT - Central Time
  • MDT - Mountain Daylight Time
  • EAST - Easter Island Standard Time
  • GALT - Galapagos Time
  • S - Sierra Time Zone

Atlantic Standard Time

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

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: Atlantic Standard Time (AST) is not adjusted for daylight saving therefore AST remains the same through out the year. This means, unlike some time zones where the clock is set forward by one hour every summer and backward by one hour during winter to adjust for daylight saving, Atlantic Standard Time remains the same

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