Millions of clocks changed themselves last night. The signal came from a radio tower in a Colorado field.

November 1, 2026

By Kim Komando

Last night at 2 a.m., millions of clocks across America turned themselves back an hour while you slept. Nobody touched them. So who did?

A radio tower in a Colorado field.

📻 The station that runs on time

It’s called WWVB, and it sits outside Fort Collins, Colo. Every second of every day, it beams the official U.S. time across most of North America on a low radio frequency.

The National Institute of Standards and Technology (NIST), the government lab that runs WWVB, estimated more than 50 million clocks and watches have a receiver.

The time itself comes from 16 atomic clocks at a lab in Boulder. They’re averaged together to keep official U.S. time. Your phone doesn’t listen to WWVB, but it gets its time from there. 

Tucked into that signal is a little flag that tells your clock, “Daylight saving time ends today.” At 2 a.m., it fell back. Like magic.

⚡ The day the clock slipped

Last December, a windstorm knocked out power to the Boulder lab. A backup generator failed. Batteries kept the atomic clocks ticking, but official U.S. time slipped 4.8 microseconds behind. That’s less than five millionths of a second.

You’d never notice. But phone networks and GPS might. NIST even weighed shutting off its internet time servers until staff got a reserve generator running.

Think about that. The whole country’s sense of “now” depends on a lab in Colorado keeping the lights on.

Here’s what didn’t change itself last night:

• The car clock, unless your car gets updates.
• The microwave, oven and coffee maker.
• Older thermostats, so check your heating schedule.
• Security cameras and DVRs, which can mess up your recording times.

Your “atomic” clock didn’t switch either? Put in fresh batteries and set it near a window facing Colorado, away from the TV. FYI, Arizona and Hawaii skip daylight saving time, so turn off the DST setting there.

Hope you enjoyed the extra hour of sleep, friend. Some strangers in Colorado earned it for you.

I was going to tell you a time-travel joke, but you didn’t like it.

🗣️ Text/post this stat: Millions of clocks changed themselves last night, and the signal came from one radio tower in a Colorado field. GetKim.com

📩 Send this to someone who still hasn’t fixed the clock on their microwave.