Daylight saving time in 2024 ended on November 3 and began on March 10

In the United States, daylight saving time (DST) started at 2 a.m. on Sunday, March 10, 2024, and ended at 2 a.m. on Sunday, November 3, 2024. On the spring date, clocks moved forward one hour. On the fall date, clocks moved back one hour. These dates are the same every year in the U.S. — the second Sunday in March and the first Sunday in November.

If you live outside the United States, the dates were different. Europe observed the change on March 31 and October 27. Other countries either do not observe daylight saving time at all or follow their own schedules. Australia, for example, changes on different dates in different states, and many countries near the equator do not shift their clocks at all.

Your devices should have updated automatically if they were connected to the internet and had automatic timezone updates turned on. However, older devices, offline systems, or those with automatic updates disabled may have required manual correction.

Key Takeaways

  • U.S. daylight saving time began March 10, 2024 (clocks forward) and ended November 3, 2024 (clocks back).
  • Devices with automatic timezone updates usually adjust on their own, but older or offline devices may need manual correction.
  • Mismatched time settings can cause login failures, missed security alerts, and problems with time-based authentication codes.
  • Check your device's timezone setting after each time change to may support it matches your actual location.

Why the time change matters for your security

When your device's clock is wrong, security features that depend on accurate time stop working correctly. Many websites and apps use time-based one-time passwords (TOTP) — those six-digit codes that expire after 30 seconds. If your device is off by even a few minutes, the code you enter will be rejected as expired, and you will be locked out of your account.

Your device's time also affects SSL certificates, which find your connection to websites. If your clock is set to a date far in the past or future, your browser will reject the certificate as invalid, even though the website is legitimate. This can make it impossible to log in or access services you normally use.

Security logs and alerts also depend on accurate timestamps. If your device time is wrong, you may miss notifications about suspicious activity, or security software may fail to record when events actually happened. This makes it harder to investigate problems later.

How to check and fix your device's time after the change

On Windows: Right-click the clock in the bottom right corner of your screen and select "Adjust date and time." The "Set time automatically" toggle should be on. If it is off, turn it on and wait a few minutes for the system to sync. If the time is still wrong after syncing, click "Sync now" under the "Additional settings" section.

On Mac: Open System Settings, click "General," then "Date and Time." Make sure "Set date and time automatically" is turned on. If the time is still incorrect, turn the toggle off, wait a few seconds, then turn it back on to force a resync.

On iPhone or iPad: Open Settings, tap "General," then "Date and Time." Turn on "Set Automatically." Your device will sync with Apple's time servers within a few minutes.

On Android: Open Settings, tap "System," then "Date and Time." Turn on "Automatic date and time" and "Automatic time zone." Some Android devices may require you to go through "Advanced settings" to find these options, depending on the manufacturer.

What to do if your device did not update automatically

Devices that are offline or have automatic updates disabled will not adjust for daylight saving time on their own. If you notice your device is one hour off after March 10 or November 3, the most reliable fix is to manually set the time and timezone.

Before you manually adjust anything, connect your device to the internet and turn on automatic date and time updates. Wait at least five minutes for the system to sync. If the time is still wrong after that, you can manually set it, but automatic sync is always the better long-term solution because it will catch future changes without your intervention.

If you use a computer that is part of a workplace network, contact your IT department before changing the time manually. Network-connected devices often sync to a central server, and manual changes can cause conflicts.

Devices and systems that may not update automatically

Older computers, especially those running Windows 7 or earlier versions of macOS, may not receive automatic timezone updates. Smart home devices like thermostats, security cameras, and smart speakers sometimes require manual updates or firmware updates to recognize the new time. Printers, network-attached storage devices, and other networked hardware often do not update on their own.

If you have devices that did not update, check the manufacturer's website or the device's settings menu for a manual time adjustment option. Some devices require you to update the firmware first before they will recognize the new timezone rules.

Routers and modems do not usually need manual adjustment because they do not display time to users, but if you have a router with a built-in clock or display, you may need to adjust it manually.

How to prevent time sync problems in the future

The simplest prevention is to keep automatic date and time updates turned on at all times. This setting is on by default on most modern devices, but it is worth checking after a major software update or if you have recently changed your timezone.

If you travel frequently, your device should automatically detect your new timezone and adjust. However, if you are in a location where the timezone is not clearly defined or your device is confused, you can manually set the timezone in your date and time settings. Once you return home, turn automatic timezone detection back on.

For devices that do not support automatic updates, set a calendar reminder for the second Sunday in March and the first Sunday in November to manually check and adjust the time. This takes less than a minute and prevents the security and authentication problems that come with incorrect time settings.

Frequently Asked Questions

Will my passwords stop working because of the time change?

Your passwords themselves will not change, but if your device's clock is wrong, time-based login codes (the six-digit numbers) will stop working. This is why fixing your device's time when ready after the change matters. Once the time is correct, your codes will work again.

What happens if I miss the time change and my device is one hour off?

You may experience login failures, especially with accounts that use two-factor authentication codes. Websites may also show security warnings about your connection. The fix is straightforward: turn on automatic date and time updates or manually set the correct time. Your accounts and connections will work normally once the time is correct.

Do I need to update my phone if it is connected to cellular service?

No. Phones connected to cellular networks receive timezone information from the carrier and update automatically. Tablets and devices that only use Wi-Fi may take a few minutes longer to sync, but they will update on their own if automatic updates are enabled.

Why do some countries not observe daylight saving time?

Countries near the equator have minimal seasonal variation in daylight, so shifting clocks provides no benefit. Some countries and U.S. states have decided the disruption to schedules, sleep, and security systems outweighs any energy savings. Hawaii, most of Arizona, and many other regions do not observe DST.

Can the time change affect my smart home devices?

Yes, if they do not update automatically. Smart speakers, thermostats, and security cameras may show the wrong time or run schedules at the wrong times. Check your device's app or settings menu for automatic timezone updates, or manually adjust the time if that option is not available.