HAA to AST Converter
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Quick answers
Selected conversion
9:00 am09:00 HAA (UTC-3), Oct 28, 2026 = 9:00 am09:00 ADT (UTC-3), Oct 28, 2026
HAA and ADT have the same local time.
HAA and AST examples
These examples always use HAA (UTC-3) and AST (UTC-4). They stay the same when you change the date or time above. The selected conversion may differ when daylight saving time applies.
HAA is 1 hour ahead of AST.
How the time difference changes
For most of the year, HAA and ADT have the same time. From Nov 1, 2026 to Mar 14, 2027, HAA is 1 hour ahead of AST.
For most of the year, working hours of 9:00 am to 6:00 pm in HAA correspond to 9:00 am to 6:00 pm in ADT. At other times of the year, working hours of 9:00 am to 6:00 pm in HAA correspond to 8:00 am to 5:00 pm in AST.For most of the year, working hours of 09:00 to 18:00 in HAA correspond to 09:00 to 18:00 in ADT. At other times of the year, working hours of 09:00 to 18:00 in HAA correspond to 08:00 to 17:00 in AST.
Compare HAA time with AST time, including current local time, UTC offsets, time difference, daylight saving changes, working hours, and shareable meeting times.
Time Difference
Heure Avancée de l'Atlantique and Atlantic Daylight Time have the same local time.
9:00 am09:00 in HAA is 9:00 am09:00 in ADT
HAA to ADT call time
Best time for a conference call or a meeting is between 9am-6pm09:00-18:00 in HAA which corresponds to 9am-6pm09:00-18:00 in ADT
9:00 am09:00 Heure Avancée de l'Atlantique (HAA). Offset UTC -3:00 hours
9:00 am09:00 Atlantic Daylight Time (ADT). Offset UTC -3:00 hours
9:00 am09:00 HAA / 9:00 am09:00 ADT
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.
| HAA | ADT |
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Heure Avancée de l'Atlantique
Offset: HAA is 3 hours behind Greenwich Mean Time (GMT).
Countries using this time zone: Bermuda, Canada, Greenland
Principal Cities: The largest city in the HAA time zone is Halifax in Canada, with about 471,559 people. Other major cities in this time zone include Sydney, Moncton, Saint John, Fredericton.
Today all shaded areas are on HAA.
Daylight Saving: Heure Avancée de l'Atlantique (HAA) is a daylight saving/summer time zone. During winter, some places set clocks back one hour and observe Atlantic Standard Time (AST).
Start: Heure Avancée de l'Atlantique (HAA) 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.
End: Heure Avancée de l'Atlantique (HAA) 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.
HAA representations, usage and related time zones
- -03 - basic short
- -0300 - basic
- -03:00 - extended
- -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.
- Papa - Military abbreviation for HAA
- P - short form of 'Papa'
- 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
Atlantic Standard Time
Offset: AST is 4 hours behind Greenwich Mean Time (GMT).
Countries using this time zone: Anguilla, Antigua and Barbuda, Aruba, Barbados, Bermuda, British Virgin Islands, Canada, Caribbean Netherlands, Curaçao, Dominica, Dominican Republic, Greenland, Grenada, Guadeloupe, Martinique, Montserrat, Puerto Rico, Saint Barthélemy, Saint Kitts and Nevis, Saint Lucia, Saint Martin, Saint Vincent and the Grenadines, Sint Maarten, Trinidad and Tobago, US Virgin Islands
Principal Cities: The largest city in the AST time zone is Santo Domingo in the Dominican Republic, with about 2.202 million people. Other major cities in this time zone include Santiago de los Caballeros, Halifax, San Juan, San Pedro de Macorís.
French: HNA - Heure Normale de l'Atlantique
Spanish: AST - Tiempo Estándar del Atlántico
Today the lighter areas are on UTC−3 (ADT).
Daylight Saving: This is a standard time zone. During summer, some places set clocks forward one hour for daylight saving time and observe Atlantic Daylight Time (ADT).
End: Atlantic Standard Time (AST) 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.
Start: Atlantic Standard Time (AST) 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 Canada daylight saving time and upcoming clock changes worldwide.
AST representations, usage and related time zones
- -04 - basic short
- -0400 - basic
- -04:00 - extended
- -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.
- Quebec - Military abbreviation for AST
- Q - short form of 'Quebec'
- 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
- Atlantic Standard Time - UTC -4
- Arabia Standard Time - UTC +3
- AST - Atlantic Standard Time
- EDT - Eastern Daylight Time
- AMT - Amazon Time
- BOT - Bolivia Time
- CDT - Cuba Daylight Time
- CLT - Chile Standard Time
- GYT - Guyana Time
- HLV - Hora Legal de Venezuela
- Q - Quebec Time Zone
- VET - Venezuelan Standard Time