AST to HST
-6hAST
ASTSOURCEHST
HSTGreen rows indicate typical business hours (9 AM - 5 PM)
AST and HST on the World Map
The map below highlights the AST (Atlantic Standard Time) and HST (Hawaii Standard Time) timezone regions across the globe.
AST – Atlantic Standard Time
UTC-04:00Atlantic Standard Time (AST) is the time zone for the Canadian Atlantic provinces and the Caribbean, 4 hours behind UTC.
- •Puerto Rico uses AST year-round and does not observe DST.
- •AST is 1 hour ahead of EST.
- •Halifax, the capital of Nova Scotia, is the largest city in AST Canada.
HST – Hawaii Standard Time
UTC-10:00Hawaii Standard Time (HST) is the time zone for the Hawaiian Islands, 10 hours behind UTC.
- •Hawaii does not observe daylight saving time.
- •HST is 5 hours behind EST in winter and 6 hours behind EDT in summer.
- •Hawaii is one of only two US states that don't observe DST (the other is Arizona).
Comparing Time Zones: AST and HST
AST runs on Atlantic Standard Time (AST) at UTC-04:00. HST runs on Hawaii Standard Time (HST) at UTC-10:00. That puts AST 6 hours behind HST — a difference of -6h at the current offsets.
In practice, when it is 9:00 AM in AST it is 3:00 AM in HST. Midnight in AST is 6:00 PM in HST. Neither zone observes daylight saving time, so the offset between them stays constant all year.
AST to HST time conversion table
| AST (AST) | HST (HST) | Day |
|---|---|---|
| 12:00 AM | 6:00 PM | previous day |
| 6:00 AM | 12:00 AM | same day |
| 7:00 AM | 1:00 AM | same day |
| 8:00 AM | 2:00 AM | same day |
| 9:00 AM | 3:00 AM | same day |
| 12:00 PM | 6:00 AM | same day |
| 3:00 PM | 9:00 AM | same day |
| 5:00 PM | 11:00 AM | same day |
| 6:00 PM | 12:00 PM | same day |
| 9:00 PM | 3:00 PM | same day |
Why people convert AST to HST time
- Scheduling a call from AST to HST: a 10:00 AM start in AST lands at 4:00 AM in HST, so you can confirm the slot without doing the arithmetic yourself.
- Finding shared working hours: both AST and HST are inside the 9-to-5 working day between 3:00 PM and 5:00 PM AST time (9:00 AM–11:00 AM HST). That is roughly 2 hours of usable overlap.
- Coordinating a AST-based team with HST contacts: quoting times in the other side's local clock — not your own — removes the single biggest source of missed meetings.
- Always state the zone abbreviation, not just the hour. "3:00 PM AST" is unambiguous; "3 PM" across a -6h gap is not.
- Block 3:00 PM–5:00 PM AST as the recurring meeting window if you work primarily from AST and need HST colleagues present.
About AST (Atlantic Standard Time)
Atlantic Standard Time (AST) covers Canada's Atlantic provinces (Nova Scotia, New Brunswick, Prince Edward Island, and most of Labrador), as well as several Caribbean nations. Puerto Rico and the US Virgin Islands use AST year-round without daylight saving time. The Canadian provinces switch to Atlantic Daylight Time (ADT) in summer.
About HST (Hawaii Standard Time)
Hawaii Standard Time (HST) is used in the state of Hawaii and does not observe daylight saving time. This makes HST one of the most consistent time zones in the US. The Hawaiian Islands are among the last places on Earth to see a new calendar day.
Best time to call between AST and HST
Both AST and HST sit inside the 9 AM – 5 PM working day between 3:00 PM–5:00 PM AST, which is 9:00 AM–11:00 AM HST. That gives roughly 2 hours of shared time — the safest window for a live call or meeting.
Business hours overlap
AST and HST overlap for about 2 hours during the working day — enough for meetings if you avoid the edges of the window.
AST is 6 hours behind HST (AST UTC-04:00 → HST UTC-10:00). The shared working window is 3:00 PM–5:00 PM AST. Remember to re-check around daylight-saving transitions.
🕐 Daylight Saving Time Info
AST
☀ Currently in DST
Standard: UTC-04:00 · DST: UTC-03:00
Clocks fall back on Sun, Nov 1, 2026
HST
Does not observe DST
Learn More About Time
Dive deeper into the fascinating world of timekeeping, time zones, and how they shape our global society:
Frequently Asked Questions
What is the time difference between AST and HST?
AST (AST, UTC-04:00) is 6 hours behind HST (HST, UTC-10:00). The gap is currently -6h.
How do I convert AST time to HST time?
Add -6h to AST local time. For example, 9:00 AM in AST is 3:00 AM in HST.
What time is it in HST right now?
HST uses HST at UTC-10:00. Use the live converter at the top of this page — it updates in real time and already accounts for the -6h offset from AST.
What is the best time to call HST from AST?
Call between 3:00 PM and 5:00 PM AST — that maps to 9:00 AM–11:00 AM HST and keeps both parties inside the working day.
Which is behind, AST or HST?
AST is 6 hours behind HST. When it is 12:00 PM in AST it is 6:00 AM in HST.
Does daylight saving time affect the AST–HST difference?
Neither zone observes daylight saving time, so the -6h offset between AST and HST is fixed all year.
Which other cities share AST's time zone?
AST also covers Halifax, San Juan, Santo Domingo, Caracas, La Paz, Fredericton, Charlottetown.
Which countries use AST, AST's zone?
AST is used in Canada (Atlantic provinces), Puerto Rico, US Virgin Islands, Dominican Republic, Venezuela, Bolivia, Barbados, Trinidad and Tobago.
Is there a day difference between AST and HST?
Not normally. The -6h gap only pushes the date over the previous day.
What is the time difference between AST and HST?
HST is -6h from AST.
What timezone is AST in?
AST operates on its local timezone.
What timezone is HST in?
HST operates on its local timezone.
Which countries use AST (Atlantic Standard Time)?
AST is used in Canada (Atlantic provinces), Puerto Rico, US Virgin Islands, Dominican Republic, Venezuela, Bolivia, and 2 more countries.
Does AST observe daylight saving time?
Yes, AST switches to ADT during summer months.
What are some interesting facts about AST?
Puerto Rico uses AST year-round and does not observe DST. AST is 1 hour ahead of EST.
Which cities are in the HST timezone?
Major cities in the HST timezone include Honolulu, Hilo, Kailua, Pearl City, Kapolei.
What is the UTC offset for HST?
Hawaii Standard Time (HST) is at UTC-10:00.
What should I know about the HST timezone?
Hawaii does not observe daylight saving time. HST is 5 hours behind EST in winter and 6 hours behind EDT in summer.
When is it midnight in AST, what time is it in HST?
When it is 12:00 AM (midnight) in AST (AST), it is -6h later in HST (HST).
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See every conversion from AST →·See every conversion from HST →