AST to HST Converter
Convert time between Atlantic Standard Time (AST) and Hawaii Standard Time (HST)
Atlantic Standard Time (AST)
Hawaii Standard Time (HST)
Time Difference
Hawaii Standard Time (HST) is 0 hours ahead of Atlantic Standard Time (AST)
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Quick Reference
| AST | HST |
|---|---|
| 22:00 | 16:00 |
| 00:00 | 18:00 |
| 02:00 | 20:00 |
| 04:00 | 22:00 |
| 06:00 | 00:00 |
| 08:00 | 02:00 |
| 10:00 | 04:00 |
| 12:00 | 06:00 |
| 14:00 | 08:00 |
| 16:00 | 10:00 |
| 18:00 | 12:00 |
| 20:00 | 14:00 |
Top 10 Most Common Time Zones
| Abbreviation | Full Name | UTC Offset | Typical Use |
|---|---|---|---|
| UTC | Coordinated Universal Time | UTC ±0 | Global reference standard (servers, logs, APIs) |
| EST / EDT | Eastern (US) Time | UTC −5 / −4 | New York, Toronto — North American business hub |
| CST / CDT | Central (US) Time | UTC −6 / −5 | Chicago, Dallas — US central business region |
| PST / PDT | Pacific (US) Time | UTC −8 / −7 | San Francisco, Los Angeles — tech industry standard |
| GMT / BST | Greenwich Mean / British Summer Time | UTC 0 / +1 | UK, used globally as a reference with UTC |
| CET / CEST | Central European (Summer) Time | UTC +1 / +2 | Paris, Berlin, Amsterdam — EU business core |
| IST | India Standard Time | UTC +5:30 | India — major IT & outsourcing region |
| CST | China Standard Time | UTC +8 | Beijing, Shanghai — East Asia business hub |
| JST | Japan Standard Time | UTC +9 | Tokyo — finance & tech hub |
| AEST / AEDT | Australian Eastern (Daylight) Time | UTC +10 / +11 | Sydney, Melbourne — APAC regional business |
Why Time Zone Abbreviations Are Ambiguous
Unlike standardized identifiers (like America/New_York or Europe/London from the IANA tz database), abbreviations such as "CST" or "IST" are not globally unique. They can refer to different time zones depending on context — country, region, or even time of year (due to daylight saving time).
Common Ambiguous Time Zone Abbreviations
| Abbrev. | Common Meaning(s) | UTC Offset | Region(s) |
|---|---|---|---|
| CST | Central Standard Time / China Standard Time / Cuba Standard Time | UTC−6 / UTC+8 / UTC−5 | North America, China, Cuba |
| IST | Indian Standard Time / Irish Standard Time / Israel Standard Time | UTC+5:30 / UTC+1 / UTC+2 | India, Ireland, Israel |
| AST | Atlantic Standard Time / Arabia Standard Time | UTC−4 / UTC+3 | Caribbean, Canada, Middle East |
| PST | Pacific Standard Time / Philippine Standard Time | UTC−8 / UTC+8 | North America, Philippines |
| EST | Eastern Standard Time (North America / Australia) | UTC−5 / UTC+10 | North America, Australia |
✅ Best Practice
To avoid ambiguity, always:
- Use IANA tz identifiers — e.g.,
America/New_Yorkinstead of "EST" - Specify UTC offset explicitly — e.g.,
UTC−5when abbreviations must be used - Include the full timezone name — e.g., "Eastern Standard Time (EST)" with UTC offset
Related Time Zone Conversions
About AST to HST Time Conversion
Converting time between Atlantic Standard Time (AST) and Hawaii Standard Time (HST) is essential for coordinating between Atlantic Canada and Hawaii during winter months. AST is UTC-4 (observed from the first Sunday in November to the second Sunday in March), while HST is UTC-10 year-round. AST is 6 hours ahead of HST during the winter season.
This conversion is crucial for businesses coordinating between Atlantic Canadian cities and Hawaii. Whether you're scheduling meetings between Halifax and Honolulu headquarters, managing distributed teams across the Atlantic and Pacific, or planning travel between Atlantic Canada and Hawaiian offices, our accurate IANA-based converter ensures precise timezone calculations. The 6-hour difference during AST season is substantial and requires careful attention to scheduling to find overlapping business hours between these distant regions.
Common Use Cases for AST to HST Conversion
Business & Work
- Scheduling Atlantic Canada to Hawaii business meetings during winter months
- Coordinating between Atlantic Canada and Hawaii headquarters during AST season
- Managing business operations across Atlantic Canada and Hawaiian regions
- Planning conference calls between Atlantic Canada and Hawaii teams during winter season
Personal & Travel
- Coordinating with family and friends in Hawaii during winter
- Planning travel between Atlantic Canada and Hawaiian destinations
- Scheduling virtual events for Atlantic Canada-Hawaii audiences during winter
- Arranging online meetings with Hawaii-based colleagues during AST months
Time Zone Information
Atlantic Standard Time (AST)
- UTC Offset: UTC-4
- IANA Timezone: America/Halifax
- Daylight Saving: Standard time (first Sunday in November to second Sunday in March)
- Major Cities: Halifax, Saint John, Fredericton, Moncton, St. John's
- Coverage: Atlantic Canada including Nova Scotia, New Brunswick, and Newfoundland (winter months)
Hawaii Standard Time (HST)
- UTC Offset: UTC-10
- IANA Timezone: Pacific/Honolulu
- Daylight Saving: No daylight saving time (consistent year-round)
- Major Cities: Honolulu, Hilo, Kailua, Maui, Kauai
- Coverage: All Hawaiian islands (consistent year-round)
Quick Reference: AST to HST
Remember: AST is 6 hours ahead of HST (during winter months, November to March). When daylight saving time begins (second Sunday in March) and AST becomes ADT, the difference increases to 7 hours. Hawaii does not observe daylight saving time, so HST remains constant year-round.
Frequently Asked Questions
What is the time difference between AST and HST?
Atlantic Standard Time (AST) is UTC-4, while Hawaii Standard Time (HST) is UTC-10. AST is 6 hours ahead of HST. When it's 2:00 PM in Halifax (AST), it's 8:00 AM the same day in Honolulu (HST).
When is AST active and how does it affect Hawaii coordination?
AST is observed from the first Sunday in November to the second Sunday in March. During this period, Atlantic Canada is 6 hours ahead of Hawaii. From March to November, when Atlantic Canada observes ADT (UTC-3), the difference increases to 7 hours. This makes winter coordination (AST season) have a smaller time gap than summer coordination.
Does Hawaii observe daylight saving time like AST does?
No, Hawaii does not observe daylight saving time. Hawaii Standard Time (HST) remains UTC-10 year-round. This is why the time difference between Hawaii and the mainland varies - the mainland changes its clocks twice per year while Hawaii stays constant. AST is specifically the winter offset for Atlantic Canada.
What major cities are in AST and HST timezones?
AST covers major Atlantic Canadian cities including Halifax, Saint John, Fredericton, Moncton, and St. John's during winter months. HST covers all Hawaiian islands with major cities being Honolulu, Hilo, Kailua, Waihuku, and Kaneohe. These regions represent Atlantic Canada during winter and the Hawaiian Islands.
What are the best times to schedule calls between AST and HST regions?
The 6-hour difference during AST season provides limited overlap. Early morning AST times (7-8 AM) correspond to very early morning HST (1-2 AM), and late morning AST (10 AM-12 PM) corresponds to very early morning HST (4-6 AM). Late afternoon AST (3-5 PM) aligns well with late morning/midday HST (9-11 AM), making this an ideal window for winter business coordination.
How does winter (AST) coordination differ from summer (ADT) coordination with Hawaii?
During winter (November-March, AST season), Atlantic Canada is 6 hours ahead of Hawaii, providing some overlap for business hours. During summer (March-November, ADT season), the difference increases to 7 hours, creating an even larger time gap. Many businesses adjust their summer schedules to accommodate these changes, with winter being slightly more favorable for synchronous communication.
Pro Tips
- • AST is always 6 hours ahead of HST during winter months (November-March).
- • When daylight saving time begins (second Sunday in March), AST becomes ADT and the difference increases to 7 hours.
- • Late afternoon AST times (3-5 PM) correspond to late morning/midday HST times (9-11 AM), ideal for coordinating business operations.
- • Hawaii does not observe daylight saving time, so HST is consistent year-round while AST changes once per season.
- • For long-term projects spanning both seasons, account for the time difference change when AST transitions to ADT in March.
- • Late afternoon AST (3-5 PM) aligns well with late morning/midday HST (9-11 AM), providing excellent overlap for winter business calls and coordination.
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