The mainland is springing forward Saturday night.
Daylight savings time begins at 2 a.m. Sunday local time in most of the mainland United States, except for much of Arizona.
Hawaii, Puerto Rico, the Virgin Islands, American Samoa, Guam and the Northern Marianas do not observe daylight savings time.
That means the time difference between Hawaii and the mainland adds an hour. So the East Coast is six hours ahead as of 8 p.m. Hawaii time and the West Coast is three hours ahead as of 11 p.m. Hawaii time.
The time change is also a good time to replace batteries in warning devices such as smoke detectors.
Daylight saving time ends Nov. 1, when clocks will fall back an hour.