AST to PST
-4hAST
ASTSOURCEPST
PSTGreen rows indicate typical business hours (9 AM - 5 PM)
AST and PST on the World Map
The map below highlights the AST (Atlantic Standard Time) and PST (Pacific 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.
PST – Pacific Standard Time
UTC-08:00Pacific Standard Time (PST) is the time zone for the US and Canadian Pacific coast, 8 hours behind UTC.
- •Silicon Valley and the world's biggest tech companies operate on Pacific Time.
- •The Hollywood film industry runs on PST/PDT.
- •PST is 3 hours behind EST, creating a significant business hours gap.
- •Vancouver, Canada's third-largest city, uses PST.
Everything You Need to Know About AST and PST Time
AST runs on Atlantic Standard Time (AST) at UTC-04:00. PST runs on Pacific Standard Time (PST) at UTC-08:00. That puts AST 4 hours behind PST — a difference of -4h at the current offsets.
In practice, when it is 9:00 AM in AST it is 5:00 AM in PST. Midnight in AST is 8:00 PM in PST. Neither zone observes daylight saving time, so the offset between them stays constant all year.
AST to PST time conversion table
| AST (AST) | PST (PST) | Day |
|---|---|---|
| 12:00 AM | 8:00 PM | previous day |
| 6:00 AM | 2:00 AM | same day |
| 7:00 AM | 3:00 AM | same day |
| 8:00 AM | 4:00 AM | same day |
| 9:00 AM | 5:00 AM | same day |
| 12:00 PM | 8:00 AM | same day |
| 3:00 PM | 11:00 AM | same day |
| 5:00 PM | 1:00 PM | same day |
| 6:00 PM | 2:00 PM | same day |
| 9:00 PM | 5:00 PM | same day |
Why people convert AST to PST time
- Scheduling a call from AST to PST: a 10:00 AM start in AST lands at 6:00 AM in PST, so you can confirm the slot without doing the arithmetic yourself.
- Finding shared working hours: both AST and PST are inside the 9-to-5 working day between 1:00 PM and 5:00 PM AST time (9:00 AM–1:00 PM PST). That is roughly 4 hours of usable overlap.
- Booking travel or deliveries: tracking PST local time against AST keeps pickup windows and arrival estimates honest across the -4h offset.
- Always state the zone abbreviation, not just the hour. "3:00 PM AST" is unambiguous; "3 PM" across a -4h gap is not.
- Block 1:00 PM–5:00 PM AST as the recurring meeting window if you work primarily from AST and need PST 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 PST (Pacific Standard Time)
Pacific Standard Time (PST) covers the west coast of North America, including tech hubs like San Francisco and Seattle, and entertainment capital Los Angeles. The Pacific Time Zone is home to Silicon Valley and the world's largest technology companies. During summer, clocks advance to Pacific Daylight Time (PDT, UTC-07:00). PST is also observed in Baja California, Mexico.
Best time to call between AST and PST
Both AST and PST sit inside the 9 AM – 5 PM working day between 1:00 PM–5:00 PM AST, which is 9:00 AM–1:00 PM PST. That gives roughly 4 hours of shared time — the safest window for a live call or meeting.
Business hours overlap
AST and PST overlap for about 4 hours during the working day — enough for meetings if you avoid the edges of the window.
AST is 4 hours behind PST (AST UTC-04:00 → PST UTC-08:00). The shared working window is 1:00 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
PST
☀ Currently in DST
Standard: UTC-08:00 · DST: UTC-07:00
Clocks fall back on Sun, Nov 1, 2026
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 PST?
AST (AST, UTC-04:00) is 4 hours behind PST (PST, UTC-08:00). The gap is currently -4h.
How do I convert AST time to PST time?
Add -4h to AST local time. For example, 9:00 AM in AST is 5:00 AM in PST.
What time is it in PST right now?
PST uses PST at UTC-08:00. Use the live converter at the top of this page — it updates in real time and already accounts for the -4h offset from AST.
What is the best time to call PST from AST?
Call between 1:00 PM and 5:00 PM AST — that maps to 9:00 AM–1:00 PM PST and keeps both parties inside the working day.
Which is behind, AST or PST?
AST is 4 hours behind PST. When it is 12:00 PM in AST it is 8:00 AM in PST.
Does daylight saving time affect the AST–PST difference?
Neither zone observes daylight saving time, so the -4h offset between AST and PST 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 PST?
Not normally. The -4h gap only pushes the date over the previous day.
What is the time difference between AST and PST?
PST is -4h from AST.
What timezone is AST in?
AST operates on its local timezone.
What timezone is PST in?
PST 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 PST timezone?
Major cities in the PST timezone include Los Angeles, San Francisco, Seattle, Vancouver, San Diego, Portland, Las Vegas, Sacramento.
What is the UTC offset for PST?
Pacific Standard Time (PST) is at UTC-08:00. During daylight saving time, it shifts to PDT.
What should I know about the PST timezone?
Silicon Valley and the world's biggest tech companies operate on Pacific Time. The Hollywood film industry runs on PST/PDT.
When is it midnight in AST, what time is it in PST?
When it is 12:00 AM (midnight) in AST (AST), it is -4h later in PST (PST).
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See every conversion from AST →·See every conversion from PST →