Pacific Standard Time (PST)
Standard offset: UTC−08:00
DST offset: UTC−07:00 (Pacific Daylight Time)
Primary IANA identifier: America/Los_Angeles
Abbreviations: PST, PDT, PT
Observed in: US West Coast, western Canada, Baja California (Mexico)
Approximate population: roughly 55 million across the three countries
If you've ever tried to schedule a call between a Hollywood studio and a New York bank, you've already met Pacific Standard Time. The three-hour gap between PST and Eastern is one of the most familiar logistical headaches in North American business. It's also the reason West Coast teams often start their day at 7 a.m. just to catch the East Coast before lunch.
PST runs eight hours behind UTC during the standard part of the year. In summer, when daylight saving kicks in, the offset shifts forward an hour to UTC−07:00, known as Pacific Daylight Time. The two together are usually just called "Pacific Time" in everyday conversation, the same way most people don't bother distinguishing EST from EDT.
Origins and Boundary Shifts
Pacific Standard Time came into being alongside the rest of North America's standard time zones in November 1883. Before that, every city kept its own solar time, which worked fine when nobody traveled faster than a horse. The railroads changed all that. Coordinating timetables across thousands of miles of track required a uniform system, and the railroads imposed one on themselves before any government got around to it.
The US Congress made the system official with the Standard Time Act of 1918. The Pacific Time Zone's eastern boundary has shifted around since then, with several states and counties petitioning over the decades to switch between Pacific and Mountain Time. Most of those movements have gone eastward. Places initially on Pacific opting to align with Mountain. The boundary in eastern Oregon and northern Idaho has been particularly fluid.
The Uniform Time Act of 1966 standardized daylight saving rules across the country. The Energy Policy Act of 2005 extended DST, pushing the spring shift forward to the second Sunday in March and the fall return to the first Sunday in November. PST follows those dates exactly.
Where Pacific Time Applies
The core of the zone is the western edge of the contiguous United States. All of California, Washington, and Oregon. The panhandle of northern Idaho. Most of Nevada, including Las Vegas, which surprises people who assume Nevada must be on Mountain Time given its location east of California.
In Canada, British Columbia uses Pacific Time, with the exception of a few eastern communities near the Alberta border that observe Mountain Time. The Yukon used to switch with the rest of Pacific Time but stopped observing DST in 2020. The territory now stays at UTC−07:00 year-round, effectively matching MST in winter and PDT in summer.
Mexico's Pacific Time territory consists of Baja California, the northern half of the peninsula, including Tijuana and Mexicali. Baja California Sur, the southern half, uses Mountain Time instead. The split isn't intuitive geographically but reflects the close economic ties between northern Baja and Southern California.
Daylight Saving and the Push for Change
Twice a year, clocks shift. The spring change moves 2:00 a.m. to 3:00 a.m. on the second Sunday of March. The fall reverses it on the first Sunday of November. Most people lose sleep in March and gain it back in November, accompanied by the predictable cycle of articles about how DST is bad for your heart.
California voters approved Proposition 7 in 2018, which authorized the state legislature to make daylight saving time permanent. The legislature hasn't acted, partly because the change would require federal approval, which hasn't come. Washington and Oregon passed similar measures. None of them can move unilaterally. Federal law doesn't allow states to adopt permanent DST on their own, though it does allow permanent standard time, which is why Arizona can opt out of DST entirely.
The Sunshine Protection Act, which would make DST permanent nationwide, passed the US Senate in 2022 but stalled in the House. Pacific states would benefit substantially. The late afternoon light in summer is already long, and locking it in year-round would mean dark winter mornings in places like Seattle, where the sun in January would not rise until close to 9 a.m.
Cities Built on Pacific Time
Los Angeles is the cultural and economic anchor. The metro area is home to about 13 million people, and the entertainment industry essentially defines the global concept of "California time." Film and television production schedules ripple outward from LA. So do music, advertising, and a substantial chunk of the social media industry.
San Francisco carries the financial and tech weight, even after the pandemic-era exodus thinned the office towers. Silicon Valley (really the South Bay around San Jose, but San Francisco gets the headlines) sets the pace for global tech. Major product launches and earnings calls are scheduled Pacific Time first, with the rest of the world adjusting.
Seattle has grown into the second tech capital, with Amazon and Microsoft headquartered in the area. The Puget Sound metro region passed 4 million in the 2020 census. Seattle's deep harbor also makes it one of the busiest ports on the West Coast.
Vancouver, British Columbia is the largest Canadian city on Pacific Time, around 2.6 million in the metro area. It functions as Canada's primary gateway to Asia, with shipping, immigration, and direct flights making the city culturally distinct from Toronto or Montreal.
San Diego sits at the southern edge of the US portion, just north of Tijuana. The two cities share a metropolitan economy that crosses the border in both directions.
Tijuana is the largest city in Mexico's Pacific Time zone, with about 1.8 million residents. The maquiladora industry, manufacturing plants serving the US market, runs on California's clock by necessity.
What It Means to Work on Pacific Time
The three-hour offset from the East Coast structures nearly everything for West Coast professionals. A 9 a.m. meeting in New York is 6 a.m. in Los Angeles. An East Coast workday that runs 9 to 5 ends at 2 p.m. Pacific. By the time California sits down to lunch, half the people they need to talk to have already gone home.
The standard solution is to wake up early. West Coast employees of East Coast firms routinely start at 6 or 7 a.m. local time to capture the overlap. Pacific-headquartered companies, on the other hand, often run their East Coast operations on local time but conduct major company-wide meetings during the late morning Pacific and early afternoon Eastern window.
There's also the Asia overlap. Tokyo is 17 hours ahead of PST (16 during PDT). Singapore is 16 hours ahead. The West Coast gets to talk to Asia during what is, for the West Coast, late afternoon or evening. That happens to be convenient enough that a lot of trans-Pacific business gets scheduled into the 4 to 8 p.m. Pacific window. People working with both Asia and the East Coast often end up with split days. Early morning for New York, late afternoon for Tokyo, and a gap in the middle for actual work.
How PST Compares to Its Neighbors
To the east, Mountain Standard Time (UTC−07:00 standard, UTC−06:00 MDT) covers the Rockies. Phoenix, however, sits in Arizona, which doesn't observe DST. So Phoenix matches PDT in summer and is one hour ahead of PST in winter. This creates the annual confusion of "is Phoenix on California time right now?" The answer flips twice a year.
To the west, Alaska Standard Time (UTC−09:00 standard, UTC−08:00 AKDT) covers most of Alaska. Anchorage is one hour behind PST in winter and matches it in summer.
Hawaii-Aleutian Standard Time at UTC−10:00 puts Honolulu two hours behind PST in winter and three hours behind during PDT. Hawaii doesn't observe DST, so the gap widens in summer.
Internationally, PST aligns with no major population centers exactly. The closest population alignment is parts of French Polynesia. During PDT, the offset matches Mexican Pacific Standard Time in Sinaloa, Sonora, and the southern half of Baja.
The transatlantic comparison most West Coast workers care about is the London one. London is eight hours ahead during PST winter, seven during PDT summer. Since British Summer Time and Pacific Daylight Time start and end on slightly different dates, there are brief windows when the gap is nine or six hours.
Notable Edge Cases
The Yukon abandoned DST in 2020, sitting on permanent UTC−07:00. This means Whitehorse matches PDT in summer and is one hour ahead of PST in winter, a small but real complication for cross-border business.
Metlakatla, Alaska, a small community on Annette Island, used to observe Pacific Time despite being inside Alaska. It switched to Alaska Time in 2015.
The Navajo Nation in northeastern Arizona observes DST, while the surrounding state does not. This creates an island of MDT-equivalent time that matches PDT in summer, surrounded by Arizona territory that matches PDT in winter and PST in summer. The Hopi Reservation, surrounded by Navajo land, doesn't observe DST either, creating a further nested exception.
Technical Identifiers
In software and the IANA Time Zone Database, Pacific Time is represented by several distinct zones:
- America/Los_Angeles, primary entry for US Pacific Time
- America/Vancouver, British Columbia
- America/Tijuana, Baja California, Mexico
- PST8PDT, legacy POSIX zone for the same offset and rules
Quick Reference
| Attribute | Value |
|---|---|
| Standard offset | UTC−08:00 |
| DST offset | UTC−07:00 (PDT) |
| DST start | Second Sunday in March |
| DST end | First Sunday in November |
| Primary IANA zone | America/Los_Angeles |
| Largest city | Los Angeles (~13M metro) |
| US states fully on PT | California, Washington, Oregon, Nevada |
| Canadian province | British Columbia (most) |
| Mexican state | Baja California |