HST to AST Converter & Meeting Planner
Quick answer: 9:00 AM HST = 3:00 PM AST (fixed -10:00 standard offset — not DST-adjusted). Use the interactive converter below for DST-aware local-time scheduling.
Planning a call or meeting between Hawaii-Aleutian Standard Time (HST) and Atlantic Standard Time (AST)? You need to account for the standard time difference. Atlantic Standard Time is normally 6 hours ahead of Hawaii-Aleutian Standard Time. Whether you are coordinating between teams in Honolulu and Hilo and Halifax and San Juan, our live tool has you covered. Use our interactive overlap studio below to find the perfect waking hours for both regions, taking into account any seasonal Daylight Saving Time (DST) changes.
24-Hour Conversion Table
Quick reference: 12:00 AM HST = 6:00 AM AST. The full 24-hour HST to AST table below uses fixed standard offsets for exact abbreviation searches.
Example: 3:00 PM HST = 9:00 PM AST.
| HST Time | AST Time |
|---|---|
| 12:00 AM (00:00) | 6:00 AM (06:00) |
| 1:00 AM (01:00) | 7:00 AM (07:00) |
| 2:00 AM (02:00) | 8:00 AM (08:00) |
| 3:00 AM (03:00) | 9:00 AM (09:00) |
| 4:00 AM (04:00) | 10:00 AM (10:00) |
| 5:00 AM (05:00) | 11:00 AM (11:00) |
| 6:00 AM (06:00) | 12:00 PM (12:00) |
| 7:00 AM (07:00) | 1:00 PM (13:00) |
| 8:00 AM (08:00) | 2:00 PM (14:00) |
| 9:00 AM (09:00) | 3:00 PM (15:00) |
| 10:00 AM (10:00) | 4:00 PM (16:00) |
| 11:00 AM (11:00) | 5:00 PM (17:00) |
| 12:00 PM (12:00) | 6:00 PM (18:00) |
| 1:00 PM (13:00) | 7:00 PM (19:00) |
| 2:00 PM (14:00) | 8:00 PM (20:00) |
| 3:00 PM (15:00) | 9:00 PM (21:00) |
| 4:00 PM (16:00) | 10:00 PM (22:00) |
| 5:00 PM (17:00) | 11:00 PM (23:00) |
| 6:00 PM (18:00) | 12:00 AM (00:00)+1 day |
| 7:00 PM (19:00) | 1:00 AM (01:00)+1 day |
| 8:00 PM (20:00) | 2:00 AM (02:00)+1 day |
| 9:00 PM (21:00) | 3:00 AM (03:00)+1 day |
| 10:00 PM (22:00) | 4:00 AM (04:00)+1 day |
| 11:00 PM (23:00) | 5:00 AM (05:00)+1 day |
Best time to call Halifax from Honolulu
For most work calls, compare the normal business day in Honolulu (HST) with the business day in Halifax (AST). HST commonly covers Pacific Ocean, North America, while AST is mainly associated with North America, Caribbean.
⚠️ Note: 2026-07-05 is not a normal workday in one or both regions based on their configured calendar. The overlap below should be treated as a reference, not a guaranteed office-hours window.
✅ The most practical overlap on 2026-07-05 is usually 9:00 AM - 10:00 AM HST, which corresponds to 4:00 PM - 5:00 PM AST. This window sits inside the typical HST workday (9:00 AM - 5:00 PM) and the AST workday (9:00 AM - 5:00 PM).
- DST Safety: HST or AST may shift during Daylight Saving Time. Always confirm the converted time for your specific date.
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Frequently Asked Questions
What is the time difference between HST and AST?
During standard time, Atlantic Standard Time is 6 hours ahead of Hawaii-Aleutian Standard Time.
Does Hawaii observe Daylight Saving Time?
Hawaii does not observe Daylight Saving Time and has not done so since 1947, remaining fixed at UTC-10:00 year-round. At roughly 20° North latitude, Hawaii's daylight hours vary by only about 1.5 hours between the summer and winter solstices — far too little to justify the disruption of a seasonal clock change.
Why is it called Hawaii-Aleutian time?
The name combines two geographically distant US territories that share the same UTC-10:00 standard offset: the Hawaiian Islands in the central Pacific and the westernmost Aleutian Islands of Alaska, which extend past the 180° meridian into the Eastern Hemisphere. Despite sharing a base offset, they behave differently — Hawaii observes no DST, while the Aleutian communities such as Adak do advance to HDT (UTC-9) each summer.
Does the Caribbean observe Daylight Saving Time?
The vast majority of Caribbean nations and territories — including Puerto Rico, the Dominican Republic, the US Virgin Islands, Trinidad and Tobago, and Barbados — do not observe Daylight Saving Time and remain on AST (UTC-4) year-round. This means these territories share the same clock as Halifax only during the Atlantic Standard Time window in winter, diverging by one hour once Canada and Bermuda advance to ADT each spring.
What is the difference between AST and ADT?
AST (Atlantic Standard Time) is the standard winter offset at UTC-4:00, observed from the first Sunday in November through the second Sunday in March across all AST regions. ADT (Atlantic Daylight Time) is the summer offset at UTC-3:00, applied by Eastern Canadian provinces and Bermuda when they advance their clocks by one hour during Daylight Saving Time.