Pacific Standard Time (UTC-8)
Los Angeles runs on this clock in winter. So does every other city on the US West Coast, British Columbia, and the border municipalities of Baja California. The fixed offset is UTC-8.
The name applies only part of the year. From the second Sunday of March to the first Sunday of November, the region moves to Pacific Daylight Time (PDT, UTC-7). Someone who says "PST" in July is technically wrong. The correct term is PDT.
Cities on this zone: Los Angeles (population 3,820,914), San Diego (1,404,452), San Francisco (827,526), Seattle (780,995), Vancouver (662,248), and Tijuana (1,922,523). The representative IANA identifier is America/Los_Angeles.
Philippine Standard Time (UTC+8)
The Philippines runs on one clock, year-round, at UTC+8. No daylight saving. No seasonal shift. PST in Manila means UTC+8 every day.
This is the dangerous one. A meeting set for "10:00 PST" could mean 10:00 in Los Angeles (UTC-8) or 10:00 in Manila (UTC+8). That is a 16-hour spread. Get it wrong and one party dials in at midnight.
Pitcairn Standard Time (UTC-8)
The Pitcairn Islands, a British Overseas Territory in the South Pacific, sit at UTC-8 all year. No daylight saving. When the US West Coast switches to PDT (UTC-7), Pitcairn falls an hour behind. When the coast returns to Pacific Standard Time in November, the two align.
Roughly 50 people live there. The scheduling risk is low. But the three letters still carry a third meaning.
Can "PST" mean all three at once?
Yes. No single authority governs time zone abbreviations. The IANA database, Unicode CLDR, and individual countries assign their own labels. The result: one abbreviation, three meanings, and a 16-hour gap between the extremes.
| Abbreviation | Full name | UTC offset | DST observed? | Region |
|---|---|---|---|---|
| PST | Pacific Standard Time | UTC-8 | Yes (switches to PDT) | US/Canada/Mexico West Coast |
| PST | Philippine Standard Time | UTC+8 | No | Philippines |
| PST | Pitcairn Standard Time | UTC-8 | No | Pitcairn Islands |
Why does "PST" cause a 16-hour scheduling gap?
Never lean on the three letters alone.
Write the full name and offset. "Pacific Standard Time (UTC-8)" or "Philippine Standard Time (UTC+8)". Not just "PST".
Put the UTC offset in every invitation. "14:00 UTC-8" is airtight. "14:00 PST" is a coin toss.
Name the city or country. "10:00 Los Angeles time" leaves no room for error.
Drop "PST" during daylight months. From March to November, the US West Coast is on PDT. Using "PST" in that window creates a one-hour mistake even when the reader guesses the right continent.
Which IANA identifier replaces "PST"?
The IANA time zone database gives every zone a unique, unchanging label. Software, calendars, and scheduling tools rely on these identifiers. They handle DST transitions automatically.
| Abbreviation | IANA identifier | What it means |
|---|---|---|
| PST (Pacific) | America/Los_Angeles | US West Coast, follows DST |
| PST (Philippine) | Asia/Manila | Philippines, no DST |
| PST (Pitcairn) | Pacific/Pitcairn | Pitcairn Islands, no DST |
Set the calendar event to America/Los_Angeles, not "PST". Same logic for Asia/Manila or Pacific/Pitcairn.
The next clock change for the Pacific zone: Sunday 01 November 2026 at 02:00 local. Clocks fall back from PDT (UTC-7) to PST (UTC-8). After that, "PST" is correct again for the US West Coast, until March 2027.