History of Pacific Time: Railroads to Daylight Saving

The Pacific Time Zone started with a single day in 1883 when every city on the West Coast reset its clocks to a single standard. This is how we got from local solar time to the system you're using to schedule a meeting right now.

Why did the railroads create Pacific Time?

Every city kept its own time, set by the sun. When it was noon in San Francisco, it was 11:58 in San Jose and 11:53 in Sacramento. Each town used its own local meridian.

That worked fine when you walked everywhere. It was a problem when you rode a train.

Railroads needed schedules. A train leaving San Francisco at 12:00 local time could not tell passengers when it would arrive in Oakland, because Oakland's clocks disagreed. By the 1870s, US railroads operated on dozens of conflicting local times. Crashes happened. Missed connections were routine.

The solution came from the railroads themselves.

The day of two noons: November 18, 1883

On that Sunday, the major US and Canadian railroads coordinated a switch to four standard time zones: Eastern, Central, Mountain, and Pacific. They called it "the day of two noons."

In each Pacific Time city, clocks stopped at their local noon, then restarted at the new standard noon for the zone. San Francisco's clocks jumped forward. Seattle's jumped forward. Los Angeles's jumped backward. Everyone reset to the 120th meridian west of Greenwich.

The railroads made it official. The US government did not. Congress let the railroad time stand for 35 years.

The Standard Time Act of 1918 and World War I

In 1918, Congress finally acted. The Standard Time Act of 1918 did two things.

First, it gave legal authority to the four time zones the railroads had been using since 1883. The Pacific Time Zone was now federal law, not just a railroad convenience.

Second, it introduced daylight saving time as a wartime fuel-saving measure. Clocks went forward in spring 1918 and back in fall 1918. The country tried it once, then repealed it a year later.

DST chaos: local option between the wars

The 1919 repeal of DST did not end the practice. It just handed the decision to local governments. Cities, counties, and states could choose whether to observe DST, and when.

The West Coast became a patchwork. Los Angeles might be on DST while San Francisco was not. Oregon observed DST in some years, skipped it in others. A traveler crossing from Portland to Seattle could lose or gain an hour without crossing a state line.

This lasted until World War II. In 1942, President Roosevelt imposed year-round DST nationwide. It stayed in effect until September 1945.

The Uniform Time Act of 1966

After the war, the patchwork returned. By the early 1960s, multiple DST schedules were in use across the US. Broadcasters, airlines, and stock exchanges demanded a fix.

The Uniform Time Act of 1966 standardized DST across the country. It set the start to the last Sunday in April and the end to the last Sunday in October. It also allowed states to exempt themselves from DST entirely by passing a state law.

Arizona and Hawaii took that exemption. No Pacific Time state did. California, Oregon, Washington, and Nevada all continued to observe DST.

The year-round DST experiment of 1974 to 1975

In 1973, the oil embargo drove fuel prices up. Congress responded with the Emergency Daylight Saving Time Energy Conservation Act. It required year-round DST for two years.

Why it started

From January 1974 to October 1975, the Pacific Time Zone stayed on PDT. No fall-back. No spring-forward.

Why it ended early

The sun rose late in Los Angeles in December. Children waited for school buses in darkness. The experiment was deeply unpopular. Congress cut it short in October 1975. The country returned to the standard April-to-October DST schedule.

The Energy Policy Act of 2005 and the 2007 extension

In 2005, Congress passed the Energy Policy Act. A provision in the bill extended DST by four weeks. Starting in 2007, DST would begin on the second Sunday of March and end on the first Sunday of November.

Canada follows the US lead

The Pacific Time Zone adopted it. Canada followed, because British Columbia's economy is tied to Washington and California. The Canadian provinces harmonized their DST schedule with the US to keep stock markets, border crossings, and broadcast schedules aligned.

California Proposition 7 and the modern DST debate

In 2018, California voters passed Proposition 7 with about 60% support. The proposition authorized the state legislature to pursue permanent DST. It did not change the clocks. It only gave permission to ask Congress for a change.

What the legislature has done

The legislature has not acted.

What the federal government has done

The federal Sunshine Protection Act, which would make DST permanent nationwide, passed the US Senate in 2022 but stalled in the House. It has not been enacted as of September 2026.

Who is waiting

California cannot switch to permanent DST without a federal law change. Neither can Oregon or Washington, which passed similar bills. British Columbia passed legislation to go permanent DST, contingent on the three West Coast states and the US Congress acting first. All wait.

Mexico's time zone evolution and the 2022 border exception

In October 2022, Mexico abolished DST nationwide. The federal government decreed that clocks would stop changing.

But not on the border.

Why Tijuana kept DST

Tijuana, Mexicali, and other border municipalities in Baja California kept DST. The reason is economic: Tijuana and San Diego are a single metropolitan area. Cross-border workers, shoppers, and maquiladora factories need the same clock. If Tijuana switched to standard time while San Diego went on DST, the border crossing would shift by an hour every spring and fall.

How the zones align

So Tijuana follows the same DST schedule as Los Angeles. The IANA time zone America/Tijuana matches America/Los_Angeles. In summer, both are UTC−7. In winter, both are UTC−8.

Region	IANA zone	Winter offset	Summer offset	DST observed?
US West Coast	America/Los_Angeles	UTC−8 (PST)	UTC−7 (PDT)	Yes
Canada (BC)	America/Vancouver	UTC−8 (PST)	UTC−7 (PDT)	Yes
Mexico border	America/Tijuana	UTC−8 (PST)	UTC−7 (PDT)	Yes
Rest of Mexico	America/Mexico_City	UTC−6	UTC−6	No

How Canada harmonized with US Pacific Time

British Columbia, where Vancouver and Surrey are on Pacific Time, has matched the US DST schedule since 2007. The province's decision was practical: Vancouver is a major port, a film production hub, and a tech center. Its business hours need to overlap with Los Angeles, San Francisco, and Seattle.

When the US moved DST to March-November in 2007, Canada followed. When the US changes DST in the future, Canada will likely follow again.

When do clocks next change in the Pacific Time Zone?

The next clock change for the Pacific Time Zone is Sunday, March 14, 2027, at 2:00 AM. Clocks go forward to 3:00 AM. PDT begins.

The change after that is Sunday, November 7, 2027, at 2:00 AM. Clocks go back to 1:00 AM. PST resumes.

If the Sunshine Protection Act ever passes, those changes stop. The zone would stay on PDT year-round. But as of September 2026, that has not happened. The next change is still March 14, 2027.

For more on the current DST rules and how they affect your schedule, see the Pacific Daylight Saving Time guide. For the zone's current boundaries and cities, see the Pacific Time Zone explained. For Tijuana's specific case, see Time in Tijuana.