PST stands for Pacific Standard Time, which is UTC-8. It is the standard, or winter, clock of the West Coast of the United States and Canada: Los Angeles, San Francisco, Seattle and Vancouver. In summer the same region switches to PDT (UTC-7) for daylight saving, and PT means whichever is current.
"PST" gets used loosely for the West Coast all year round, but it is technically only correct for about four months of the year. The rest of the time the coast is on PDT. Knowing the difference is the difference between a call that lands on time and one that is an hour out.
What does PST stand for?
PST is short for Pacific Standard Time. It is the time zone covering the Pacific coast of North America when daylight saving is not in effect. Its offset is UTC-8, meaning it runs eight hours behind Coordinated Universal Time. When it is 12:00 noon in London (winter), it is 4:00 AM in Los Angeles.
The word that matters is standard. "Standard time" is the baseline a region keeps for the darker half of the year, before clocks are advanced for summer. PST is therefore the Pacific coast's winter baseline. It is the same idea as GMT for the UK or EST for the US East Coast: the resting offset before daylight saving lifts it by an hour.
Where is PST used?
Pacific Standard Time is the winter clock for the western edge of the US and Canada. The main cities are below.
| City | Country | Winter (PST) |
|---|---|---|
| Los Angeles | United States | UTC−8 |
| San Francisco | United States | UTC−8 |
| Seattle | United States | UTC−8 |
| Vancouver | Canada | UTC−8 |
What is the difference between PST and PDT?
They are the same region, one hour apart, depending on the season. PST is the standard winter time; PDT is the summer daylight saving time. Clocks "spring forward" to PDT in March and "fall back" to PST in November. So a city like San Francisco is on PST for roughly four months and PDT for the other eight, even though people call it "PST" all year out of habit.
| Label | Full name | Offset | When |
|---|---|---|---|
| PST | Pacific Standard Time | UTC−8 | Winter |
| PDT | Pacific Daylight Time | UTC−7 | Summer |
| PT | Pacific Time | Either | Whichever is current |
From roughly March to November the West Coast is on PDT, not PST, so a "9 AM PST" invite in July is technically an hour off. When in doubt, write PT, which always points to the active offset. For the full list of these labels, see time zone abbreviations explained.
How many hours behind EST is PST?
PST is 3 hours behind EST (Eastern Standard Time). When it is 12:00 noon in New York, it is 9:00 AM in Los Angeles. That three-hour gap is the classic coast-to-coast spread, and it holds whenever both coasts are on standard time. If you schedule across the US a lot, it is worth understanding the Eastern side too: see EST vs EDT.
PST at a glance
| When it's 12:00 noon PST | It is |
|---|---|
| New York (EST) | 3:00 PM |
| London (GMT) | 8:00 PM |
| UTC | 8:00 PM |
| Sydney (AEDT) | 7:00 AM next day |
What it means for scheduling
The practical takeaway: don't hard-code "PST" into a recurring invite. The West Coast offset shifts twice a year, and if your invite says PST while the coast is on PDT, you will be an hour out. The safest habit is to read each person's actual local time rather than do the arithmetic, which is exactly what Atlas shows you, daylight saving shifts and all.
Frequently asked
What does PST mean?
What is the difference between PST and PDT?
How many hours behind EST is PST?
Is California PST or PDT right now?
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