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ADT
12am
3am
6am
9am
12pm
3pm
6pm
9pm
CDT/CST
UTC−5
2h behind
12am
3am
6am
9am
12pm
3pm
6pm
9pm
Central Time is on daylight saving time: CDT (UTC−5) until Sun, Nov 1.

Mexico City and Saskatchewan stay on CST (UTC−6).

Quick answers

Selected conversion

9:00 am09:00 ADT (UTC-3), Oct 18, 2026 = 7:00 am07:00 CDT (UTC-5), Oct 18, 2026

ADT is 2 hours ahead of CDT.

ADT and CST (US winter time, UTC-6) examples

These examples always use ADT (UTC-3) and CST (UTC-6). They stay the same when you change the date or time above. The selected conversion may differ when daylight saving time applies.

ADT is 3 hours ahead of CST.

CST is US Central winter time (early November to mid-March). The rest of the year Chicago uses CDT (UTC-5), one hour later. For Central Time that follows daylight saving time, use ADT to CT. For daylight-time examples, use ADT to CDT.

How the time difference changes

For most of the year, ADT is 2 hours ahead of CDT. From Nov 1, 2026 to Mar 14, 2027, AST is 2 hours ahead of CST. Briefly around clock changes, ADT is 3 hours ahead of CST or AST is 1 hour ahead of CDT.

For most of the year, working hours of 9:00 am to 6:00 pm in ADT correspond to 7:00 am to 4:00 pm in CDT. At other times of the year, working hours of 9:00 am to 6:00 pm in AST correspond to 7:00 am to 4:00 pm in CST.For most of the year, working hours of 09:00 to 18:00 in ADT correspond to 07:00 to 16:00 in CDT. At other times of the year, working hours of 09:00 to 18:00 in AST correspond to 07:00 to 16:00 in CST.

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

Time Difference

Atlantic Daylight Time is 2 hours ahead of Central Daylight Time.
9:00 am09:00 in ADT is 7:00 am07:00 in CDT

ADT to CDT call time
Best time for a conference call or a meeting is between 11am-6pm11:00-18:00 in ADT which corresponds to 9am-4pm09:00-16:00 in CDT

9:00 am09:00 Atlantic Daylight Time (ADT). Offset UTC -3:00 hours
7:00 am07:00 Central Daylight Time (CDT). Offset UTC -5:00 hours

9:00 am09:00 ADT / 7:00 am07:00 CDT

Choose an hour to update the converter. Day labels such as “next day” or “+1” are relative to the selected date in the first column. Use Up and Down arrow keys, Home or End to move between hours, then Enter or Space to select.

Hourly time comparison
ADTCDT
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Atlantic Daylight Time

Offset: ADT is 3 hours behind Greenwich Mean Time (GMT).

Countries using this time zone: Bermuda, Canada, Greenland

Principal Cities: The largest city in the ADT time zone is Halifax in Canada, with about 471,559 people. Other major cities in this time zone include Sydney, Moncton, Saint John, Fredericton.

French: HAA - Heure Avancée de l'Atlantique

Map of the areas on Atlantic Daylight Time (ADT)
ADT part of the year

Today all shaded areas are on ADT.

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

123456789101112Start: Atlantic Daylight Time (ADT) started on Sunday, March 8, 2026 at 2:00 am02:00 local time and clocks were set one hour forward to Sunday, March 8, 2026, 3:00 am03:00. Daylight saving starts annually on the second Sunday of March.

123456789101112End: Atlantic Daylight Time (ADT) ends on Sunday, November 1, 2026 at 2:00 am02:00 local time and clocks are set one hour back to Sunday, November 1, 2026, 1:00 am01:00 local standard time instead. Daylight saving ends annually on the first Sunday of November.

See Canada daylight saving time and upcoming clock changes worldwide.

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 - Brasilia Time
  • CLST - Chile Summer Time
  • FKST - Falkland Islands Summer Time
  • FKT - Falkland Islands Time
  • GFT - French Guiana Time
  • P - Papa Time Zone
  • PYST - Paraguay Summer Time
  • PYT - Paraguay Time
  • SRT - Suriname Time
  • UYT - Uruguay Time

Central Standard Time

Offset: CST is 6 hours behind Greenwich Mean Time (GMT).

Countries using this time zone: Belize, Canada, Costa Rica, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, United States

Principal Cities: The largest city in the CST time zone is Mexico City in Mexico, with about 12.294 million people. Other major cities in this time zone include Chicago, Houston, Puebla, Santiago de Querétaro.

French: HNC - Heure Normale du Centre

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

Map of the areas on Central Standard Time (CST)
CST all year CST part of the year

Today the lighter areas are on UTC−5 (Central Daylight Time).

Daylight Saving: This is a standard time zone. During summer, some places set clocks forward one hour for daylight saving time and observe Central Daylight Time (CDT).

123456789101112End: Central Standard Time (CST) ended on Sunday, March 8, 2026 at 2:00 am02:00 local time and clocks were set one hour forward to Sunday, March 8, 2026, 3:00 am03:00 local daylight time instead. Standard time ends annually on the second Sunday of March.

123456789101112Start: Central Standard Time (CST) starts on Sunday, November 1, 2026 at 2:00 am02:00 local time and clocks are set one hour back to Sunday, November 1, 2026, 1:00 am01:00. Standard time starts annually on the first Sunday of November.

See USA daylight saving time and upcoming clock changes worldwide.

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 an offset of six hours 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/Chihuahua
  • 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/Ojinaga
  • 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
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