Fall back happens on the first Sunday in November

In the United States, clocks move back one hour at 2 a.m. on the first Sunday of November. That means the night between Saturday and Sunday, you lose an hour of sleep but gain an hour on the clock — 2 a.m. becomes 1 a.m. again. In 2024, that Sunday is November 3rd. In 2025, it's November 2nd.

Not every country or region follows this schedule. Most of Europe moves clocks back on the last Sunday of October. If you work with people in other time zones or travel across borders, the dates matter because the time difference between you and them shifts for a few weeks each year.

Your phone, computer, and tablet usually handle the change automatically if you have automatic time zone updates turned on. But if you manually set your time, or if a device hasn't received a recent software update, you may need to adjust it yourself.

Key Takeaways

  • Clocks in the United States fall back one hour at 2 a.m. on the first Sunday in November, moving from Eastern, Central, Mountain, or Pacific Daylight Time back to Standard Time.
  • Most devices update automatically if automatic time zone settings are enabled, but older devices or those without recent updates may require manual adjustment.
  • The time change affects security features that depend on accurate time, including password expiration, two-factor authentication codes, and certificate validation for encrypted connections.
  • Europe and other regions change on different dates, so coordinating with people in other time zones requires knowing when each location switches.

Why your device's time matters during the clock change

When your device's clock is wrong, security systems that rely on time can fail silently. Two-factor authentication codes expire after 30 seconds — if your device thinks it's a different time than the server does, the code you enter will be rejected even though you typed it correctly. Password reset links often work for only a few hours, and if your clock is behind, a link that should still be valid may appear expired.

Encrypted connections use time to verify that security certificates are still valid. If your device's clock is set to a date far in the past, your browser may refuse to connect to websites because it thinks the certificate has expired. This is why banks and payment sites sometimes stop working after a clock change — not because of the change itself, but because a device somewhere in the chain has the wrong time.

The clock change itself is not the problem. The problem is devices that don't update automatically and get left behind, creating a mismatch between what your device thinks the time is and what the rest of the world thinks it is.

How to check if your device will update automatically

On Windows: Open Settings, go to Time & language, then Date & time. Look for a toggle that says "Set time automatically" — if it's on, Windows will update when the clock changes. If it's off, you'll need to manually change your clock on November 3rd.

On Mac: Open System Settings, click General, then Date & Time. Check the box next to "Set date and time automatically" — if it's checked, your Mac will handle the change. If you've unchecked it, you'll need to update manually.

On iPhone or iPad: Go to Settings, tap General, then Date & Time. Turn on "Set Automatically" — this uses your cellular network or Wi-Fi to get the correct time. If you've turned this off, the device won't update.

On Android: Open Settings, go to System, then Date & time. Turn on "Automatic date & time" and "Automatic time zone" — both need to be on for the device to update without your help.

What to do if your device doesn't update automatically

If you've disabled automatic updates or own an older device that doesn't support them, you'll need to manually set the time after the clock change. On November 3rd at 2 a.m., subtract one hour from the displayed time — so if your device shows 2:15 a.m., change it to 1:15 a.m.

The easiest approach is to wait until after 3 a.m. on November 3rd, then manually set your device to the correct time. By then, most of the world will have already changed, and you can look at your phone's time against a reliable source like a bank website or a radio station's clock.

After you change the time manually, check that your time zone is also correct. A device set to the right time but the wrong time zone will still cause problems with two-factor codes and certificate validation. On most devices, the time zone setting is right next to the time setting in the date and time menu.

Time zones that don't observe daylight saving time

Hawaii, most of Arizona, and U.S. territories like Puerto Rico and the U.S. Virgin Islands do not observe daylight saving time. If you live in or frequently contact people in these places, their clocks won't change on November 3rd. This means the time difference between you and them shifts by one hour for a few weeks.

If you travel to one of these regions, your phone will usually update automatically to the local time zone when it connects to the local cellular network. But if you've disabled automatic time zone updates, you'll need to manually change your time zone setting when you arrive.

Coordinating with people in other countries

Europe changes clocks on the last Sunday of October — this year, October 27th. That means for a week, Europe is one hour ahead of the usual difference. If you normally call someone in London at 3 p.m. Eastern Time, during that week you'll need to call at 4 p.m. Eastern Time instead.

Australia's time zones change on different dates depending on the state, and some Australian states don't observe daylight saving at all. Japan, China, and India never change their clocks. If you work across multiple time zones, the easiest approach is to schedule meetings using a time zone converter that accounts for daylight saving time — most calendar apps like Google Calendar and Outlook do this automatically.

What usually goes wrong after the clock change

The most common problem is a device that updates the time but not the time zone, or vice versa. This creates a one-hour offset that breaks two-factor authentication and makes calendar events appear at the wrong time. If you notice that codes aren't working after November 3rd, check both the time and the time zone setting — they're separate things.

The second common problem is a device that doesn't update at all because automatic updates are disabled. If you can't log into accounts or websites refuse to connect after the clock change, the first thing to check is whether your device's time matches the actual time. Compare it to your phone's clock, a bank website, or a radio station's website.

Older computers and devices that haven't received a software update in several years may not know about the clock change at all. If you own a device like this, manually setting the time is your only option.

Frequently Asked Questions

Do I lose an hour of sleep when clocks fall back?

No — you gain an hour. When clocks fall back at 2 a.m., that hour happens again, so you sleep through 1 a.m. to 2 a.m. twice. In practice, most people sleep through the change and straightforward wake up to a clock that shows an earlier time than expected.

Will my calendar events move to a different time after the clock change?

If your calendar app is set to your correct time zone and updates automatically, events should stay at the same local time. If your time zone setting is wrong or didn't update, events may appear one hour off. Check your calendar app's time zone setting after November 3rd if events look wrong.

What if my two-factor codes stop working after the clock change?

Check that your device's time and time zone are both correct — they're separate settings. If they are correct and codes still don't work, restart the device and try again. If the problem continues, you may need to use a backup code or contact the service's support team.

Do I need to change my passwords after the clock change?

No. The clock change itself doesn't affect your passwords. If you're locked out of an account after the clock change, the problem is usually a wrong time or time zone setting, not a security breach.

What time does the clock change happen in my state?

In all U.S. states that observe daylight saving time, clocks change at 2 a.m. local time on the first Sunday in November. The exact moment is the same everywhere — it's just expressed in each state's local time. Hawaii, Arizona, and U.S. territories don't change their clocks at all.