Daylight saving time in the United States changes on the second Sunday of March and the first Sunday of November

In 2024, clocks spring forward one hour at 2 a.m. on Sunday, March 10, and fall back one hour at 2 a.m. on Sunday, November 3. In 2025, the spring change happens on Sunday, March 9, and the fall change happens on Sunday, November 2. The exact date shifts each year because it is tied to those specific weeks, not a fixed calendar date.

When clocks spring forward in March, you lose an hour of sleep that night. When they fall back in November, you gain an hour. Most of the United States observes daylight saving time, though Hawaii, most of Arizona, and some U.S. territories do not change their clocks at all.

Key Takeaways

  • Daylight saving time changes happen at 2 a.m. on the second Sunday in March (spring forward) and the first Sunday in November (fall back).
  • In 2024, spring forward is March 10 and fall back is November 3; in 2025, spring forward is March 9 and fall back is November 2.
  • Hawaii, most of Arizona, and some U.S. territories do not observe daylight saving time and do not change their clocks.
  • The time change affects alarm clocks, phone clocks, and any device that does not update automatically, so manual adjustment may be needed.

Why the clock changes on these specific dates

Congress set the daylight saving time schedule in the Uniform Time Act of 1966. The law chose the second Sunday in March and the first Sunday in November to standardize when the change happens across states that observe it. Before that law, states changed their clocks on different dates, which created confusion for transportation, broadcasting, and business.

The reasoning behind daylight saving time itself is to shift an hour of daylight from morning to evening during warmer months, when people are more likely to be awake in the evening. Whether this actually saves energy or provides other benefits is debated, but the schedule itself has remained the same since 1966.

How to prepare for the time change

The easiest preparation is to change your clocks before bed on the night of the change. Most smartphones, computers, and modern appliances update automatically if they are connected to the internet or a network. Older devices—alarm clocks, car clocks, ovens, and microwaves—usually need to be adjusted by hand.

In March, when you spring forward, set clocks ahead one hour. In November, when you fall back, set clocks back one hour. If you have many devices to adjust, doing it the evening before makes the morning less hectic. Some people set a phone reminder a few days before to give themselves time to remember which devices need manual changes.

Devices that may not update automatically

Smartphones and computers almost always update on their own if they have internet access and automatic time updates turned on. However, some devices require manual adjustment. Car clocks, microwave clocks, oven clocks, and older alarm clocks typically do not update themselves. Smartwatches may or may not update depending on the brand and whether they are synced to a phone.

If you have a device that did not update and you are unsure how to change it, check the user manual or the manufacturer's website for instructions. Most devices have a settings menu where you can manually set the time. Taking a few minutes to adjust these before the change takes effect prevents confusion about what time it actually is.

Time zones that do not observe daylight saving time

Hawaii and most of Arizona stay on the same time year-round and do not change their clocks. The U.S. Virgin Islands, Guam, American Samoa, and Puerto Rico also do not observe daylight saving time. If you live in or are calling someone in one of these places, remember that the time difference between your location and theirs may shift by an hour after the change happens on the mainland.

For example, if you are in California and someone you know is in Hawaii, the time difference is normally two hours. But after California springs forward in March, the difference becomes three hours until Hawaii's time stays the same. Keeping track of this is especially important for scheduling calls or video meetings with people in these areas.

What to do if your device does not update

If you notice a device is showing the wrong time after the change, locate the time settings. On most devices, this is in a settings or preferences menu. Look for options labeled "Date and Time," "Time Zone," or "Automatic Time Update." If automatic updates are turned off, turn them on and the device should sync to the correct time within a few minutes.

If automatic updates are already on but the time is still wrong, the device may not have internet access or may need to be restarted. Restarting often forces the device to check for the correct time. If the device is very old or does not support automatic updates, you will need to adjust it manually using the time-setting menu.

Frequently Asked Questions

Do I lose or gain an hour of sleep when clocks change?

In March, when clocks spring forward, you lose an hour of sleep because the hour from 2 a.m. to 3 a.m. does not happen that night. In November, when clocks fall back, you gain an hour because the hour from 1 a.m. to 2 a.m. happens twice.

What time do the clocks actually change?

The change happens at 2 a.m. local time. At that moment, clocks jump to 3 a.m. in March or back to 1 a.m. in November. Most people are asleep, so the change happens without them noticing it happen in real time.

Will my phone automatically update to the new time?

Yes, if your phone has internet access and automatic time updates are turned on in settings. Most modern smartphones update within minutes of the official change. If your phone does not update, check that automatic time is enabled in the date and time settings.

What if I forget to change my clock?

You will be an hour off until you remember to adjust it. This can cause you to be late to appointments or miss scheduled events. Setting a phone reminder a few days before the change helps prevent this.

Do all states in the US change their clocks?

No. Hawaii, most of Arizona, and some U.S. territories do not observe daylight saving time. Most other states do change their clocks, though a few states have tried to change the law. Check your local area to confirm whether the time changes where you live.