AST to PST Time Converter
PST is 4 hours behind AST. Atlantic Canada and the Caribbean are currently on ADT (UTC-3:00), and The US West Coast is currently on PDT (UTC-7:00).
Best Time to Call Between AST and PST
Both zones are inside normal business hours between 1:00 PM and 5:00 PM AST — that's 9:00 AM to 1:00 PM PST. That's a 4-hour window.
both at work AST only PST only neither — hours along the strip are AST.
Common Times Converted
AST on the left, PST on the right.
AST to PST: Full 24-Hour Conversion Table
Shaded rows are working hours; the darker shade marks the hours when both zones are at work.
| AST | PST | Working hours |
|---|---|---|
| 12:00 AM | 8:00 PM prev day | — |
| 1:00 AM | 9:00 PM prev day | — |
| 2:00 AM | 10:00 PM prev day | — |
| 3:00 AM | 11:00 PM prev day | — |
| 4:00 AM | 12:00 AM | — |
| 5:00 AM | 1:00 AM | — |
| 6:00 AM | 2:00 AM | — |
| 7:00 AM | 3:00 AM | — |
| 8:00 AM | 4:00 AM | — |
| 9:00 AM | 5:00 AM | AST only |
| 10:00 AM | 6:00 AM | AST only |
| 11:00 AM | 7:00 AM | AST only |
| 12:00 PM | 8:00 AM | AST only |
| 1:00 PM | 9:00 AM | Both zones |
| 2:00 PM | 10:00 AM | Both zones |
| 3:00 PM | 11:00 AM | Both zones |
| 4:00 PM | 12:00 PM | Both zones |
| 5:00 PM | 1:00 PM | PST only |
| 6:00 PM | 2:00 PM | PST only |
| 7:00 PM | 3:00 PM | PST only |
| 8:00 PM | 4:00 PM | PST only |
| 9:00 PM | 5:00 PM | — |
| 10:00 PM | 6:00 PM | — |
| 11:00 PM | 7:00 PM | — |
What AST and PST Actually Are
AST — Atlantic Standard Time
Halifax, San Juan, Santo Domingo, Bermuda. Standing at UTC-4:00 as written, and the region does change its clocks, so its live offset moves by an hour twice a year. The next change is on Sunday, November 1, 2026, to AST. AST also stands for Arabia Standard Time (UTC+3), used in Saudi Arabia, Iraq and Kuwait.
Atlantic Standard Time is the only North American zone whose name is more commonly associated, worldwide, with a completely different zone — Arabia Standard Time.
PST — Pacific Standard Time
Los Angeles, San Francisco, Seattle, Las Vegas, Vancouver. Standing at UTC-8:00 as written, and the region does change its clocks, so its live offset moves by an hour twice a year. The next change is on Sunday, November 1, 2026, to PST. The Philippines occasionally uses PST for Philippine Standard Time (UTC+8); PHT is the clearer label for that.
California voted in 2018 to move to permanent daylight time, but the change needs an act of Congress and has never happened, so PST is still the winter standard.
What This Means in Practice
Both sides change clocks, on different dates
Both regions observe daylight saving but do not switch on the same day, so for a week or two each spring and fall the gap between them is an hour different from the rest of the year. Those short windows are where recurring invitations quietly break.
Major Cities in Each Zone
Cities on AST
Cities on PST
Frequently Asked Questions
What is the time difference between AST and PST?
PST is 4 hours behind AST.
What is 9:00 AM AST in PST?
9:00 AM AST is 5:00 AM PST.
What are the best hours to schedule a call between AST and PST?
Between 1:00 PM and 5:00 PM AST, which is 9:00 AM to 1:00 PM PST. Both sides are inside normal business hours through that window.
Does the difference between AST and PST change during the year?
Yes. Both regions observe daylight saving, and they do not switch on the same dates, so the gap shifts by an hour at least twice a year. The next clock change is on Sunday, November 1, 2026.
Does AST always mean Atlantic Standard Time?
AST also stands for Arabia Standard Time (UTC+3), used in Saudi Arabia, Iraq and Kuwait.
Does PST always mean Pacific Standard Time?
The Philippines occasionally uses PST for Philippine Standard Time (UTC+8); PHT is the clearer label for that.