The Reason Daylight Saving Time Begins at 2 a.m.

If you happen to be awake and staring at your smartphone in the very early hours of the morning on Sunday, November 6, you’ll have the small pleasure of watching the time jump right from 1:59 a.m. to 1:00 a.m. Daylight saving time (DST), of course, is the reason you’re gaining an hour of sleep—but why that hour, specifically?

As TIME explains, the United States first adopted DST in 1918 as a way to conserve energy during World War I, following the lead of both England and Germany. When choosing exactly when to make the switch, officials were looking for an hour that could easily disappear without wreaking havoc on people’s schedules across the nation. Since no Amtrak trains departed New York City on Sundays at 2 a.m., losing that hour seemed a little less consequential than any other.

“Sunday morning at 2 a.m. was when would interrupt the least amount of train travel around the country,” Michael Downing, author of Spring Forward: The Annual Madness of Daylight Saving Time, told TIME.

The United States didn’t stick with daylight saving time after 1918—partially because so many farmers opposed it—but it did resurrect the tradition during World War II, and Congress formalized the practice in 1966 with the Uniform Time Act (which also created the time zones we use today).

The reason DST’s 2 a.m. start time has remained standard through the years isn’t just because it prevents confusion among late-night train passengers. Considering that most bars and restaurants are closed by then, and early shift-workers won’t be awake yet, it’s a pretty quiet hour across the board.

Wondering how daylight saving time will affect sunrise and sunset times in your area? Here’s a map for that.