HST to ADT Converter
Time Difference
Hawaii Standard Time is 7 hours behind Atlantic Daylight Time
2:30 pm14:30 in HST is 9:30 pm21:30 in ADT
HST to ADT call time
Best time for a conference call or a meeting is between 8am-11am in HST which corresponds to 3pm-6pm in ADT
2:30 pm14:30 Hawaii Standard Time (HST). Offset UTC -10:00 hours
9:30 pm21:30 Atlantic Daylight Time (ADT). Offset UTC -3:00 hours
2:30 pm14:30 HST / 9:30 pm21:30 ADT
HST | ADT |
---|---|
12am (midnight) | 7am |
1am | 8am |
2am | 9am |
3am | 10am |
4am | 11am |
5am | 12pm (noon) |
6am | 1pm |
7am | 2pm |
8am | 3pm |
9am | 4pm |
10am | 5pm |
11am | 6pm |
12pm (noon) | 7pm |
1pm | 8pm |
2pm | 9pm |
3pm | 10pm |
4pm | 11pm |
5pm | 12am (midnight) |
6pm | 1am |
7pm | 2am |
8pm | 3am |
9pm | 4am |
10pm | 5am |
11pm | 6am |
0:00 | 7:00 |
1:00 | 8:00 |
2:00 | 9:00 |
3:00 | 10:00 |
4:00 | 11:00 |
5:00 | 12:00 |
6:00 | 13:00 |
7:00 | 14:00 |
8:00 | 15:00 |
9:00 | 16:00 |
10:00 | 17:00 |
11:00 | 18:00 |
12:00 | 19:00 |
13:00 | 20:00 |
14:00 | 21:00 |
15:00 | 22:00 |
16:00 | 23:00 |
17:00 | 0:00 |
18:00 | 1:00 |
19:00 | 2:00 |
20:00 | 3:00 |
21:00 | 4:00 |
22:00 | 5:00 |
23:00 | 6:00 |
Hawaii Standard Time
Offset: HST is 10 hours behind Greenwich Mean Time (GMT) and is used in Pacific
Countries: It is used in following countries: United States
Principal Cities: The largest city in the HST timezone is Honolulu from USA with population about 371,657 people. Other major cities in the area are Pearl City, Hilo, Kailua, Waipahu
Daylight Saving: Hawaii Standard Time (HST) is not adjusted for daylight saving therefore HST 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, Hawaii Standard Time remains the same

HST representations, usage and related time zones
- -10 - basic short
- -1000 - basic
- -10:00 - extended
- -1000 - sign character (-) followed by a four digit time providing hours (10) and minutes (00) of the offset. Indicates ten hour and zero minutes time differences to the west of the zero meridian.
- Whiskey - Military abbreviation for HST
- W - short form of 'Whiskey'
- America/Adak
- America/Atka
- HST
- Pacific/Honolulu
- Pacific/Johnston
- US/Aleutian
- US/Hawaii
- HAST - Hawaii-Aleutian Standard Time
- CKT - Cook Island Time
- HST - Hawaii Standard Time
- TAHT - Tahiti Time
- W - Whiskey Time Zone
Atlantic Daylight Time
Offset: ADT is 3 hours behind Greenwich Mean Time (GMT) and is used in North America
Countries: It is used in following countries: Bermuda, Canada, Greenland
Principal Cities: The largest city in the ADT timezone is Halifax from Canada with population about 359,111 people. Other major cities in the area are Sydney, Dartmouth, Saint John, Moncton
French: HAA - Heure Avancée de l'Atlantique

Daylight Saving: Atlantic Daylight Time (ADT) is a daylight saving/summer timezone, however during winter some places switch clocks for one hour back and observe Atlantic Standard Time (AST).
Start: Atlantic Daylight Time (ADT) started on Sunday, March 9, 2025 at 2:00 am local time and clocks were set one hour forward to Sunday, March 9, 2025, 3:00 am. Daylight saving starts annually the on second Sunday of March
End: Atlantic Daylight Time (ADT) ends on Sunday, November 2, 2025 at 2:00 am local time and clocks are set one hour back to Sunday, November 2, 2025, 1:00 am local standard time instead. Daylight saving ends annually the on first Sunday of November
ADT 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 three hour and zero minutes time differences to the west of the zero meridian.
- Papa - Military abbreviation for ADT
- P - short form of 'Papa'
- America/Glace_Bay
- America/Goose_Bay
- America/Halifax
- America/Moncton
- America/Thule
- Atlantic/Bermuda
- Canada/Atlantic
- ADT - Atlantic Daylight Time
- PMT - Pierre & Miquelon Standard Time
- PMST - Pierre & Miquelon Standard Time
- WGT - West Greenland Time
- AMST - Amazon Summer Time
- ART - Argentina Time
- BRT - BrasÃlia 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