standard time

standard time also slow time  {n.}

Clock time that is set by law or agreement in a country or in part of a country; especially, in the United States: the clock time used between fall and spring, which is an hour slower than the time used in the summer. — Abbreviation ST.

When we go to bed Saturday night, we will set our clocks back an hour, because Sunday we will be on standard time again.

Next week it will get dark an hour earlier, because we will be on standard time.

Contrast: DAYLIGHT SAVING TIME.