Time to turn back your clocks

You can get more sleep tonight as the clock is turned back an hour, marking the end of daylight saving time.

Most of the nation will return to standard time at 2 a.m., the U.S. National Institute of Standards and Technology said on its website. The change is commonly observed in the Northern Hemisphere, adding an hour of daylight in the morning.

Daylight saving time begins on the second Sunday in March and ends on the first Sunday in November after the U.S. Congress passed legislation in 2005 to extend the standard-time period by several weeks. The time change was first observed in the U.S. in 1918.

The practice isn't mandatory for states. Arizona, Hawaii and the U.S. territories of American Samoa, Guam, Puerto Rico and the U.S. Virgin Islands don't observe the time change.