Change your clock on the second Sunday in March and the first Sunday in November

In the United States, daylight saving time begins on the second Sunday in March at 2:00 a.m. local time — clocks spring forward one hour. It ends on the first Sunday in November at 2:00 a.m. local time — clocks fall back one hour. Most people change their clocks the night before, when it is easier to remember and less disruptive.

Not every state observes daylight saving time. Hawaii and most of Arizona do not change their clocks at all. Some U.S. territories, including Puerto Rico, Guam, and the U.S. Virgin Islands, also stay on standard time year-round. If you live in one of these places, you do not need to change your clock.

The dates are the same every year, so you can mark them on your calendar now. Many phones and computers change automatically, but clocks in your car, kitchen, and bedroom usually require manual adjustment.

Key Takeaways

  • Clocks move forward one hour on the second Sunday in March and back one hour on the first Sunday in November.
  • Most people change their clocks the evening before the official time change, around bedtime.
  • Hawaii, Arizona (except the Navajo Nation), and U.S. territories do not observe daylight saving time.
  • Smartphones and computers usually update automatically, but you will need to manually change clocks in your car, kitchen, and bedroom.
  • The time change affects when sunrise and sunset occur, which can take a few days to adjust to.

Why the dates are the second Sunday and the first Sunday

Congress set these specific dates in the Uniform Time Act of 1966. Before that, states and cities chose their own dates, which created confusion for transportation, broadcasting, and business. The second Sunday in March and the first Sunday in November were chosen to balance the needs of farmers, schools, and energy use.

The dates have stayed the same since 2007, when Congress moved the start date earlier in the year. Before 2007, daylight saving time began on the first Sunday in April. This change was intended to save energy, though research on whether it actually does remains mixed.

How to change clocks in your home

Start with the clocks you use most often: your bedroom alarm clock, kitchen clock, and car clock. Most analog clocks (with hands) can be adjusted by turning the hour hand forward or backward. Digital clocks usually have a button or menu option labeled "time" or "set" — check the clock's manual or look for a small button on the back or side.

Microwave clocks, oven clocks, and thermostat displays often require you to hold down a button while using arrow keys to change the hour. Some thermostats change automatically if they are connected to WiFi. Older car clocks may require you to press and hold a button on the dashboard, while newer vehicles with touchscreens usually have a settings menu under "vehicle" or "system."

If you have a clock you cannot figure out, take a photo of it and search online for "[brand name] clock how to set time." Most manufacturers post instructions on their websites or YouTube.

What happens to your body when clocks change

When you lose an hour in March, you may feel tired for a few days because your body's internal clock is still on the old schedule. When you gain an hour in November, you might wake up earlier than usual for a few days. These effects are usually mild and fade within a week as your body adjusts to the new sunrise and sunset times.

Some people find the spring change harder than the fall change because losing sleep is more disruptive than gaining it. If you struggle with the time change, try going to bed 15 minutes earlier for a few days before the change in March, or staying up 15 minutes later for a few days before the change in November.

Devices that change automatically

Most smartphones, tablets, and computers update their clocks automatically as long as you have the correct time zone set. iPhones and Android phones update through your carrier's network. Windows computers and Macs update through their operating systems. You do not need to do anything — the change happens at 2:00 a.m. on the scheduled date.

Smart home devices like Amazon Alexa and Google Home also update automatically if they are connected to the internet. However, older devices, car infotainment systems, and appliances with built-in clocks often do not update on their own. Check your device's settings or manual to see whether it has an automatic time update feature.

States and territories that do not change clocks

Hawaii has not observed daylight saving time since 1967. Most of Arizona does not change clocks either, though the Navajo Nation (which spans parts of Arizona, New Mexico, and Utah) does observe daylight saving time. U.S. territories including Puerto Rico, Guam, the U.S. Virgin Islands, American Samoa, and the Northern Mariana Islands stay on standard time year-round.

If you travel between a state that observes daylight saving time and one that does not, you may cross a one-hour time difference. For example, when most of the country springs forward in March, Arizona stays on standard time, creating a two-hour difference between Arizona and California instead of the usual one hour.

Frequently Asked Questions

Do I need to change my phone's clock?

No. Your phone updates automatically as long as you have the correct time zone selected in settings. Check your phone's clock app or settings to confirm it shows the right time after the change occurs.

What time should I change my clock?

The official change happens at 2:00 a.m., but most people change their clocks the night before around bedtime. This is easier to remember and less disruptive than waking up at 2:00 a.m. to adjust them.

What if I forget to change my clock?

You will be an hour off until you change it manually. There is no penalty for forgetting — just adjust your clock whenever you notice the time is wrong. Many people catch it within a day or two.

Does my car clock change automatically?

Most older car clocks do not change automatically. Newer vehicles with connected infotainment systems may update through their GPS or internet connection, but you should check your car's manual to be sure. If it does not update, you can change it manually using the dashboard controls.

Why do we still do daylight saving time if it does not save energy?

That is a question many people ask. Congress has the power to change or eliminate daylight saving time, but there is no agreement on whether to stay on standard time year-round or daylight time year-round. Some states have asked Congress for permission to stay on daylight time permanently, but federal law currently requires the time change twice a year.