The Hawaiian Islands’ standard time has a UTC offset of UTC−10:00. Known as Hawaiian Standard Time, or HST, it places Hawaii ten hours behind Coordinated Universal Time.
Hawaii remains on standard time throughout the year and does not observe daylight saving time. As a result, its clock does not move forward in spring or backward in autumn, unlike clocks in most U.S. states. The nearby Aleutian Islands are part of the same Hawaii–Aleutian time-zone designation, but the Alaskan portion can observe daylight saving time while Hawaii cannot.
The current UTC−10:00 standard replaced an earlier Hawaiian offset of UTC−10:30. Hawaii’s territorial legislature approved the change in 1947, and the new standard took effect on June 8 of that year. The zone’s name reflects its geographic reach across Hawaii and the Aleutian chain.
Hawaii’s time is often confused with Alaska’s, but Alaska generally uses UTC−09:00 standard time. The state’s lack of daylight saving time also means Hawaii can be one or two hours farther behind the U.S. West Coast, depending on the season.