Daylight saving time, also known as daylight savings time or daylight time, and summer time, is the practice of advancing clocks during warmer months so that darkness falls at a later clock time.

Do we lose or gain an hour?

Daylight saving time in the fall means we “fall back” and — depending on your outlook — we lose an hour during the day or we gain an extra hour of sleep. ... For 2021, the time change happens at 2 a.m. Sunday, Nov. 7.

Which states don't do Daylight Savings Time?

The two states that do not follow DST are Arizona and Hawaii. The territories of American Samoa, Guam, The Northern Mariana Island, Puerto Rico and the U.S. Virgin Islands also do not observe DST.