Don't forget to set your clocks ahead an hour before heading to bed Saturday night.
Sunday at 2 a.m. marks the beginning of daylight saving time, when Americans "spring forward" and effectively gain an hour of evening sunlight.
DST was first observed in the United States in 1918 and was implemented as a way to conserve energy. The thought was that with more sunlight in the evenings, there would be less need for artificial lighting.
That idea actually dates back to Benjamin Franklin, and the logic behind it has largely held true, though advances in technology have made artificial lighting much cheaper, cleaner and easier over the years.
The support of DST varies. While many like the added evening sunlight in the summer, many others contend that changing clocks is disruptive to sleep schedules, according to WebExhibits.org. Others still say energy isn't really saved by the switch, as the extra sunlight encourages people to go out—and use gasoline—later into the night.
As a sign of the varying popularity of DST, Arizona and Hawaii—along with Puerto Rico, American Samoa, Guam, Northern Mariana Islands and the United States Virgin Islands—currently don't recognize DST.
Clocks will switch back on Nov. 4 this year.