Under federal law, all standard time zones in the country are set to the internationally adopted Coordinated Universal Time.  The state of Washington is located in the Pacific Time Zone, along with California, Nevada, most of Oregon, and a part of Idaho.  Standard time in the Pacific Time Zone is known as Pacific Standard Time, which is offset by negative eight hours from Coordinated Universal Time.  
 
The federal Uniform Time Act of 1966 standardized the use of a daylight saving time within the standard time zones of the United States.  Daylight saving time refers to the time of year where daily time shifts forward one hour from standard time.  Daylight saving spans from the second Sunday in March through the first Sunday in November.  Under the Uniform Time Act a state may exempt itself from daylight saving time. 

Federal law provides two ways in which an area in the United States can be moved from one standard time zone to another.  First, Congress may enact a federal law.  Second, a state or local government, by formal request of a governmental official or body, may provide detailed information to the United States Secretary of Transportation supporting the requesting party's contention the requested change would serve the convenience of commerce.

In 2019, the Legislature passed SHB 1196 which provides that Washington State and all of its political subdivisions will follow Pacific Daylight Time—which is Pacific Standard Time advanced by one hour—throughout the year if federal law changes to allow the state to observe daylight savings time year-round.  To date, Congress has not passed legislation to allow states to observe daylight savings time year-round.  

The state of Washington exercises its right under the Uniform Time Act to exempt itself from daylight savings time and would remain on the time designated by the United States Department of Transportation under the Uniform Time Act—which is currently Pacific Standard Time—year-round.

The act would expire following the effective date of federal legislation allowing the state to observe daylight saving time year-round at which point Washington State and all of its political subdivisions would observe Pacific Daylight Time year-round.