What Is the Pacific Time Zone?

What does Pacific Time mean?

An invite lands: "3:00 PM Pacific." You are in New York. Do you join at 6:00 PM or 5:00 PM? The answer depends on which Pacific Time is running that day.

Pacific Time is the general label for the clock used on the west coast of the United States and Canada, plus a strip of Mexican border cities. It is not a fixed offset from Coordinated Universal Time (UTC). It shifts by one hour twice a year because of daylight saving time.

The term "Pacific Time" (PT) is the safe umbrella term. Use it when you do not know whether it is standard or daylight time. Use it in recurring calendar invites. Use it when talking to someone outside the zone.

PST vs PDT: the two faces of Pacific Time

Pacific Standard Time (PST) is the winter clock. It runs from early November to early March. Its offset is UTC−8. When it is noon in Los Angeles in January, it is 20:00 UTC.

Pacific Daylight Time (PDT) is the summer clock. It runs from early March to early November. Its offset is UTC−7. When it is noon in Los Angeles in July, it is 19:00 UTC.

The difference is one hour. That one hour is why a call scheduled for 10:00 AM Pacific in December starts at 1:00 PM in New York, but the same call in June starts at 1:00 PM in New York too. Eastern Time also shifts. The gap between Pacific and Eastern is always three hours, all year. The gap between Pacific and London, by contrast, changes: 8 hours in winter, 8 hours in summer if you compare PST to GMT and PDT to BST. The UK and US switch on slightly different dates, so there is a short period each spring and fall when the difference is 7 or 9 hours.

When does the Pacific Time Zone change its clocks?

The transition dates are set by US federal law. Canada and the Mexican border municipalities follow the same schedule to keep commerce synchronized.

In 2026: - Pacific Daylight Time begins Sunday 8 March at 02:00 local time. Clocks spring forward to 03:00. - Pacific Standard Time returns Sunday 1 November at 02:00 local time. Clocks fall back to 01:00.

In 2027: - Pacific Daylight Time begins Sunday 14 March at 02:00 local time. - Pacific Standard Time returns Sunday 7 November at 02:00 local time.

The change always happens on a Sunday at 02:00 local time. Most people are asleep and fewer systems are disrupted. If you are scheduling something during the transition weekend, check whether your meeting falls before or after the change.

What are the UTC offsets for PST and PDT?

PST is UTC−8. PDT is UTC−7.

That is the single most useful number to remember. If you know UTC, you can compute Pacific Time in your head. If you know another zone's offset, you can subtract.

For example, London in winter is UTC+0. London in summer is UTC+1 (BST). So: - January, London 12:00 → PST 04:00 (12 − 8 = 4) - July, London 12:00 → PDT 04:00 (12 − 8 = 4 again, because both shifted)

The offset pair PST/PDT is identical to the pattern used by Mountain Time in winter and Central Time in summer. That causes confusion. Phoenix, Arizona uses Mountain Standard Time all year (UTC−7). In summer, Phoenix matches PDT. In winter, Phoenix is one hour ahead of PST.

Why the abbreviation matters for scheduling

"PST" is the most misused time zone abbreviation on the internet.

Many digital calendars, news websites, and TV listings display "PST" throughout the year, even in July. That is technically wrong. When it is July, the correct abbreviation is PDT. If your calendar shows "PST" for a summer event, the time is probably correct. The software is just using the wrong label. But if the software actually calculated the time using a UTC−8 offset, the time would be wrong by one hour.

Always verify the offset, not the abbreviation. If you see "PST" on an event in August, check the UTC offset shown. If it says UTC−8, the event is one hour later than it should be. If it says UTC−7, the label is sloppy but the time is right.

Common mistakes: using PST all year

Colloquially, people say "PST" for everything. "I'll call you at 2 PM PST" in June is common. Technically it is wrong. Practically, the person means Pacific Time. The safest correction is to say "Pacific Time" or "PT" in spoken conversation and in written invitations.

The problem is not just sloppiness. Some systems genuinely apply the wrong offset. If you book a flight or a train for July and the confirmation says "PST", call to confirm. Amtrak and airlines use local time at each station, but third-party booking sites sometimes hardcode PST.

PST abbreviation conflicts: Philippine Standard Time

PST also means Philippine Standard Time. That is UTC+8. The same three letters stand for a zone on the opposite side of the planet.

If you are scheduling a call between Los Angeles and Manila, "10:00 AM PST" is ambiguous. It could mean 10:00 AM in California (UTC−8 in winter) or 10:00 AM in the Philippines (UTC+8). The difference is 16 hours.

Pitcairn Standard Time also uses PST. Pitcairn is a tiny island in the Pacific Ocean with a population of about 50. It uses UTC−8 all year with no daylight saving. That is a third meaning for the same abbreviation.

The solution: write the offset. "10:00 AM PST (UTC−8)" or "10:00 AM PT" makes the intent clear.

States and provinces on Pacific Time

United States: - California (entire state) - Washington (entire state) - Oregon (most of the state; a small area around Ontario in the east uses Mountain Time) - Nevada (most of the state; a small area near Wendover uses Mountain Time) - Idaho (the northern panhandle, including Coeur d'Alene; the rest of Idaho uses Mountain Time)

Canada: - British Columbia (most of the province; the Peace River region around Fort St. John uses Mountain Time all year; the southeastern corner around Cranbrook also uses Mountain Time)

Mexico: - Baja California (the border municipalities of Tijuana, Mexicali, Ensenada, and Tecate use Pacific Time with DST. The rest of Baja California state, south of Ensenada, uses Pacific Standard Time all year without DST.)

Not all Pacific-facing areas are on Pacific Time. The Alaska panhandle uses Alaska Time (UTC−9/−8). Yukon uses Mountain Standard Time all year (UTC−7, no DST). Hawaii uses Hawaii-Aleutian Standard Time (UTC−10, no DST).

Major cities in the Pacific Time Zone

The border zone: Tijuana and Mexicali

Mexico abolished nationwide daylight saving time in October 2022. But the border municipalities that share economies with US cities were exempted. Tijuana, Mexicali, Ensenada, and Tecate continue to observe DST on the same schedule as the United States.

This means Tijuana and San Diego are always on the same time. A worker crossing the border at 8:00 AM does not lose or gain an hour. A maquiladora factory in Tijuana shipping goods to a warehouse in Los Angeles operates on the same clock.

The IANA zone identifier for these cities is America/Tijuana, not America/Los_Angeles. The two zones are identical in behavior, but the geographic metadata is different.

Pacific Time vs other US time zones

The difference between Pacific and the other mainland US zones is constant all year because they all observe DST on the same dates. The Alaska difference is also constant: Alaska is one hour behind Pacific. Hawaii is two hours behind Pacific in winter, three hours behind in summer (Hawaii does not observe DST).

IANA time zone identifiers for Pacific Time

Software uses IANA identifiers, not abbreviations. The three identifiers for Pacific Time are:

• America/Los_Angeles, used by most of the US and Canadian cities in the zone
• America/Vancouver, used by Canadian cities including Vancouver and Surrey
• America/Tijuana, used by the Mexican border cities

If you are writing code or setting up a server, use one of these identifiers. Do not hardcode UTC offsets. Do not use "PST" or "PDT" as a time zone key. The IANA database accounts for DST transitions and historical changes automatically.

Why "Pacific Time" is the safest term to use

"Pacific Time" means the same thing in January and July. It is unambiguous. It does not trigger the PST-vs-Philippine-Standard-Time confusion. It is understood by scheduling software, calendar apps, and human beings.

Use PT for: - Recurring meetings that span DST transitions - Written invitations sent weeks in advance - Any communication with people who are not time zone experts

Use PST or PDT only when you are certain which one is in effect and you want to be precise. If you say "3:00 PM PST" in August, you are technically wrong even if everyone knows what you mean.

What to do next: Check the current time in the zone. If it is between November and March, visit the PST Time Now page. If it is between March and November, visit the PDT Time Now page. For a full list of cities on this zone, see the cities in the Pacific Time Zone page.