WASHINGTON (AP) -- Daylight saving time arrives this weekend in the United States.
Most Americans will set their clocks 60 minutes forward before heading to bed Saturday night, and most smart phones should update automatically. Daylight saving time officially starts Sunday at 2 a.m. local time (0600 GMT).
Daylight saving time promises an extra hour of evening light for months ahead.
The time change is not observed by Hawaii, most of Arizona, Puerto Rico, the Virgin Islands, American Samoa, Guam and the Northern Marianas.
The change mean that in the eastern time zone the United States is four hours behind Greenwich Mean Time instead of five.
Daylight saving time ends Nov. 1.
National Institute of Standards and Technology: http://www.nist.gov/pml/div688/dst.cfm