PST vs PDT: What’s the Difference?
PST and PDT both refer to US Pacific Time — one zone, one identifier, with the offset shifting by an hour depending on daylight saving time.
PST (Pacific Standard Time) and PDT (Pacific Daylight Time) both describe the US West Coast time zone — cities like Los Angeles, San Francisco, and Seattle. Like EST/EDT on the East Coast, they’re the same underlying zone, not two different ones.
The offsets
- PST (standard time, roughly November–March): UTC−8
- PDT (daylight saving time, roughly March–November): UTC−7
The IANA identifier America/Los_Angeles stays constant year-round; only the offset changes automatically when daylight saving time starts and ends.
If you’re coordinating with the US West Coast, don’t hard-code "PST" into a recurring calendar invite — use a tool that resolves the actual time zone so the meeting time stays correct across the DST transition.