The practice of falling back in the U.S. started in 1918 during World War I as a way to conserve fuel. By moving the clocks ahead an hour, backers believed the country could divert a bit of coal-fired electricity to the military instead of using it for an hour of home power. It was reenacted in World War II.

This November, when daylight saving time ends for 2025, clocks will "fall back," meaning those affected will gain an extra hour of sleep. But for some regions of the country, the time change will also mean an earlier sunset and more hours in the dark of night.