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CST/CDT
Cuba Standard Time
GMT -5
12am
3am
6am
9am
12pm
3pm
6pm
9pm
CDT is not used on this date
This converter uses CST (GMT -5), the offset Havana uses on this date. Open the CST converter.
AST/ADT
Atlantic Standard Time
GMT -4
12am
3am
6am
9am
12pm
3pm
6pm
9pm
ADT is not used on this date
This converter uses AST (GMT -4), the offset Moncton uses on this date. Open the AST converter.

Quick answers

For most of the year, CDT Caribbean is 1 hour behind ADT. During seasonal clock changes, CST Caribbean is 1 hour behind AST. Briefly around those changes, CDT Caribbean and AST have the same time.

For most of the year, working hours of 9:00 am to 5:00 pm in CDT Caribbean correspond to 10:00 am to 6:00 pm in ADT. During seasonal clock changes, working hours of 9:00 am to 5:00 pm in CST Caribbean correspond to 10:00 am to 6:00 pm in AST.

Compare CDT time with ADT time, including current local time, UTC offsets, time difference, daylight saving changes, working hours, and shareable meeting times.

Time Difference

Cuba Standard Time is 1 hour behind Atlantic Standard Time
7:00 am07:00 in CST is 8:00 am08:00 in AST

CST to AST call time
Best time for a conference call or a meeting is between 9am-4pm in CST which corresponds to 10am-5pm in AST

7:00 am07:00 Cuba Standard Time (CST). Offset UTC -5:00 hours
8:00 am08:00 Atlantic Standard Time (AST). Offset UTC -4:00 hours

7:00 am07:00 CST / 8:00 am08:00 AST

CSTAST
12am (midnight)1am
1am2am
2am3am
3am4am
4am5am
5am6am
6am7am
7am8am
8am9am
9am10am
10am11am
11am12pm (noon)
12pm (noon)1pm
1pm2pm
2pm3pm
3pm4pm
4pm5pm
5pm6pm
6pm7pm
7pm8pm
8pm9pm
9pm10pm
10pm11pm
11pm12am (midnight)
00:0001:00
01:0002:00
02:0003:00
03:0004:00
04:0005:00
05:0006:00
06:0007:00
07:0008:00
08:0009:00
09:0010:00
10:0011:00
11:0012:00
12:0013:00
13:0014:00
14:0015:00
15:0016:00
16:0017:00
17:0018:00
18:0019:00
19:0020:00
20:0021:00
21:0022:00
22:0023:00
23:0000:00

Cuba Daylight Time

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

Countries using this time zone: Cuba

Principal Cities: The largest city in the CDT time zone is Havana in Cuba, with about 2.164 million people. Other major cities in this time zone include Santiago de Cuba, Camaguey, Holguin, Guantanamo.

Daylight Saving: Cuba Daylight Time (CDT) is a daylight saving/summer time zone, but some places set clocks back one hour during winter and observe Cuba Standard Time (CST).

Daylight saving time clock moves forward for one hour from 1am to 2amEnd: Cuba Daylight Time (CDT) ended on Sunday, November 2, 2025 at 1:00 am local time and clocks were set one hour back to Sunday, November 2, 2025, 12:00 am local standard time instead. Daylight saving ends annually on the first Sunday of November

Daylight saving time clock moves back for one hour from 12am to 11pmStart: Cuba Daylight Time (CDT) starts on Sunday, March 8, 2026 at 12:00 am local time and clocks are set one hour forward to Sunday, March 8, 2026, 1:00 am. Daylight saving starts annually on the second Sunday of March

CDT 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 an offset of four hours to the west of the zero meridian.
Military/NATO: Used by the U.S. military, Chinese military and others
  • Quebec - Military abbreviation for CDT
  • Q - short form of 'Quebec'
IANA/Olson: Reflects CDT time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • America/Havana
  • Cuba
CDT Abbreviation: Several time zones share CDT abbreviation and it could refer to these time zones
  • Central Daylight Time - UTC -5
  • Cuba Daylight Time - UTC -4
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

Atlantic Daylight Time

Offset: ADT is 3 hours behind Greenwich Mean Time (GMT) and is used in North America

Countries using this time zone: Bermuda, Canada, Greenland

Principal Cities: The largest city in the ADT time zone is Halifax in Canada, with about 359,111 people. Other major cities in this time zone include Sydney, Dartmouth, Saint John, Moncton.

French: HAA - Heure Avancée de l'Atlantique

ADT Time Zone Geo Map
ADT timezone map

Daylight Saving: Atlantic Daylight Time (ADT) is a daylight saving/summer time zone, but some places set clocks back one hour during winter and observe Atlantic Standard Time (AST).

Daylight saving time clock moves forward for one hour from 2am to 3amEnd: Atlantic Daylight Time (ADT) ended on Sunday, November 2, 2025 at 2:00 am local time and clocks were set one hour back to Sunday, November 2, 2025, 1:00 am local standard time instead. Daylight saving ends annually on the first Sunday of November

Daylight saving time clock moves back for one hour from 2am to 1amStart: Atlantic Daylight Time (ADT) starts on Sunday, March 8, 2026 at 2:00 am local time and clocks are set one hour forward to Sunday, March 8, 2026, 3:00 am. Daylight saving starts annually on the second Sunday of March

ADT representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • -03 - basic short
  • -0300 - basic
  • -03:00 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • -0300 - sign character (-) followed by a four digit time providing hours (03) and minutes (00) of the offset. Indicates an offset of three hours to the west of the zero meridian.
Military/NATO: Used by the U.S. military, Chinese military and others
  • Papa - Military abbreviation for ADT
  • P - short form of 'Papa'
IANA/Olson: Reflects ADT time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • America/Glace_Bay
  • America/Goose_Bay
  • America/Halifax
  • America/Moncton
  • America/Thule
  • Atlantic/Bermuda
  • Canada/Atlantic
Time zones with the GMT -3 offset:
  • ADT - Atlantic Daylight Time
  • PMT - Pierre & Miquelon Standard Time
  • PMST - Pierre & Miquelon Standard Time
  • AMST - Amazon Summer Time
  • ART - Argentina Time
  • BRT - Brasília time
  • CLST - Chile Summer Time
  • FKST - Falkland Islands Summer Time
  • GFT - French Guiana Time
  • P - Papa Time Zone
  • PYST - Paraguay Summer Time
  • SRT - Suriname Time
  • UYT - Uruguay Time