UTC to PST Converter

Pacific Standard Time (PST) is the civil time of the entire US west coast: Los Angeles, San Francisco, Seattle, Portland, San Diego, Sacramento, Las Vegas, Reno, Vancouver in British Columbia, and the western portions of Mexico's Baja California (which is now on a separate but aligned schedule). PST sits eight hours behind Coordinated Universal Time (UTC-8) during winter and seven hours behind (UTC-7, Pacific Daylight Time) during summer Daylight Saving Time. The IANA America/Los_Angeles identifier encodes the full transition history, including the 1918 Standard Time Act and every Energy Policy Act amendment through 2007.

Conversion from UTC is straightforward: subtract eight hours from UTC during the winter months (November-March) and seven hours during PDT (early March to early November). Because PST is so far west, the date in Los Angeles is often one day earlier than the UTC date. A wire timestamp of 06:00 UTC on Tuesday is still 22:00 PST on Monday - a critical gotcha for trans-Pacific finance, entertainment, and aerospace operations. The Hollywood Sign on Mount Lee in Los Angeles and the Golden Gate Bridge across the strait into San Francisco serve as the visual anchors of this calculator.

Pacific Standard Time was created by the Standard Time Act of 1918, signed by President Woodrow Wilson on 19 March 1918. The Act established the four contiguous US zones anchored on meridians 75°, 90°, 105°, and 120° west of Greenwich. Before 1918 the Southern Pacific Railroad and the Union Pacific Railroad together used over a dozen different local times in their California timetables, leading to chronic dispatch conflicts. The 120° west meridian passes through Hyder, Alaska and crosses the eastern edge of the Sierra Nevada near Mono Lake before exiting the US into Baja California.

Daylight Saving Time on the west coast follows the same federal pattern: PDT starts on the second Sunday of March and ends on the first Sunday of November. California, Oregon, and Washington have all passed legislative resolutions requesting Congress make PDT year-round, but federal approval is required and has not been granted. The legal authority for DST is the Uniform Time Act of 1966 as amended by the Energy Policy Act of 2005. Arizona (excluding the Navajo Nation) is the only conterminous US state that does not observe DST, sitting on Mountain Standard Time year-round while neighboring California swings between PST and PDT.

Coordinated Universal Time, the international reference for time, was adopted in 1972 as the successor to Greenwich Mean Time. UTC is steered by the Bureau International des Poids et Mesures (BIPM) in Sevres, France, via an ensemble of more than 400 atomic clocks worldwide, including the cesium-fountain clocks at NIST in Boulder, Colorado, and the US Naval Observatory in Washington DC. UTC ticks on the SI second, defined since 1967 by 9 192 631 770 cycles of cesium-133 ground-state transition radiation, and is occasionally adjusted by leap seconds to remain within 0.9 seconds of mean solar time at Greenwich.

Modern timezone software, including the dual UTC and PST panels rendered above, draws on the IANA Time Zone Database (TZDB), founded by Arthur David Olson at the National Institutes of Health in 1986 and now maintained collaboratively at iana.org/time-zones. The identifier America/Los_Angeles encodes every DST rule change since 1883, including the 1918 Standard Time Act, the 1942-1945 War Time period, the 1966 Uniform Time Act, the 1986 amendments, and the 2007 Energy Policy Act extensions. Every Linux, macOS, iOS, Android, and modern browser ships a copy of this database.

The economic stakes of UTC-to-PST conversion are large. Silicon Valley venture capitalists, Hollywood studio executives, Pacific Crest aerospace engineers, and the entire trans-Pacific maritime shipping industry all need to convert UTC to local Pacific time reliably. Bitcoin perpetual swaps on Binance and OKX stamp in UTC. SpaceX launch windows from Vandenberg are published in UTC. Netflix streaming telemetry, Amazon AWS region status pages, and Google Cloud incident reports all use UTC reference times that must be cross-walked to PST for local incident response. A Burbank entertainment studio scheduling a Tokyo licensing call uses UTC as the canonical scheduling time.

Citation footnotes for this page: the ISO 8601 international standard codifies the date-time string format used throughout this calculator. UTC is referenced in 49 CFR (US Department of Transportation regulations) for air traffic control. Federal Aviation Administration regulations under 14 CFR require all flight plans and ATC clearances in the conterminous US to use UTC (informally called Zulu time). The NIST radio time signal WWV in Fort Collins, Colorado, and WWVH in Kekaha, Hawaii, broadcast UTC continuously on shortwave. PST is recognised in California Government Code section 6809 and Title 49 of the United States Code.