The United States changes clocks on the second Sunday in March and the first Sunday in November

In 2024, clocks spring forward on March 10 and fall back on November 3. In 2025, the spring change happens on March 9 and the fall change on November 2. The change always occurs at 2 a.m. local time — when spring forward arrives, you lose an hour of sleep that night, and when fall back arrives, you gain an hour.

Not every state observes daylight saving time. Hawaii and most of Arizona stay on standard time year-round. Some U.S. territories, including Puerto Rico, Guam, and the U.S. Virgin Islands, also do not change their clocks. If you live in one of these places or travel to one, the local time will not shift on those dates.

The shift affects more than just your clock. Banks, schools, hospitals, and government offices all operate on the new time. Your phone and computer typically update automatically, but older devices, appliances, and car clocks may not.

Key Takeaways

  • Daylight saving time in the U.S. begins on the second Sunday in March (spring forward) and ends on the first Sunday in November (fall back).
  • The time change happens at 2 a.m., meaning you lose an hour of sleep in March and gain an hour in November.
  • Hawaii, most of Arizona, and several U.S. territories do not observe daylight saving time and keep the same time all year.
  • Most phones and computers update automatically, but you may need to manually adjust older devices, car clocks, and appliances.
  • The change affects business hours, school schedules, and appointment times, so check with your employer or service providers if you are unsure.

What happens to your sleep when clocks change

When you spring forward in March, you set your clock ahead one hour at 2 a.m., which means 2 a.m. becomes 3 a.m. when ready. If you normally wake at 7 a.m., your body clock still wakes you at what feels like 7 a.m., but the clock reads 8 a.m. You lose an hour of sleep that night, and many people report feeling groggy the next day.

When you fall back in November, you set your clock back one hour at 2 a.m., which means 2 a.m. becomes 1 a.m. You get an extra hour in bed, though some people find the sudden shift disorienting. The darkness arrives earlier in the evening, which can affect mood and energy levels for a few days.

Most people adjust within a few days to a week. If you have a rigid sleep schedule or a condition sensitive to time changes, you may want to gradually shift your bedtime a few days before the change rather than adjusting all at once.

Which devices update automatically and which do not

Smartphones, tablets, and computers connected to the internet update automatically in most cases. Your phone pulls the correct time from your wireless carrier or internet connection, so you do not have to do anything. The same is true for smart home devices like Alexa or Google Home, as long as they are connected to Wi-Fi.

Devices that do not connect to the internet — car clocks, microwave clocks, oven clocks, older alarm clocks, and wall clocks — require manual adjustment. Some car models have a menu option to change the time; others require you to hold a button or use a specific sequence. Check your car's manual or search the model number online if you are unsure how to adjust it.

Smartwatches and fitness trackers usually update if they sync with your phone, but older digital watches do not. Thermostats, security system panels, and some appliances may or may not update depending on whether they have internet access. If a device matters for your schedule — like an alarm clock or a work timer — test it the day after the change to confirm it updated correctly.

How to prepare in the days before the change

A few days before the change, make a list of devices you use regularly that might not update on their own. This includes your car, kitchen appliances, bedside alarm clock, and any wall clocks in your home or office. Check the manuals or manufacturer websites for instructions on how to adjust each one.

If you have medical equipment, security systems, or work-related devices that depend on accurate time, contact the provider or manufacturer ahead of time. Some systems update automatically through a connection you may not be aware of, and calling ahead prevents confusion on the day of the change.

On the night of the change, set a phone reminder for the morning so you remember to check that your adjustments worked. This is especially important if you have an early appointment or meeting the next day — you want to confirm your car clock and alarm clock are showing the correct time.

Time zones and daylight saving time across the country

The continental United States spans four time zones: Eastern, Central, Mountain, and Pacific. All of them change on the same dates — the second Sunday in March and the first Sunday in November — but the actual time of day differs. When it is 2 a.m. in New York (Eastern), it is 1 a.m. in Chicago (Central), midnight in Denver (Mountain), and 11 p.m. the previous day in Los Angeles (Pacific).

If you work or communicate across time zones, the change happens simultaneously everywhere, so the time difference between zones stays the same. A meeting scheduled for 10 a.m. Eastern time remains 9 a.m. Central time before and after the change.

Alaska and Hawaii observe their own time zones and do not change their clocks. If you are scheduling a call with someone in Hawaii while you are on the mainland, remember that Hawaii stays on standard time year-round, so the time difference between you and Hawaii changes by an hour twice a year.

States and regions that do not change their clocks

Hawaii has not observed daylight saving time since 1967. Most of Arizona also stays on standard time year-round, though the Navajo Nation within Arizona does observe daylight saving time. The U.S. territories of Puerto Rico, Guam, American Samoa, and the U.S. Virgin Islands do not change their clocks.

Some states have proposed legislation to stay on daylight saving time permanently or to switch to standard time permanently, but federal law currently requires states to observe one or the other. A state can choose standard time year-round without federal permission, but staying on daylight saving time year-round requires a federal exemption, which is difficult to obtain.

If you are moving to or visiting one of these places, check the local time before you travel. A flight arriving in Hawaii at what your phone says is 6 p.m. may actually be 4 p.m. local time if you are traveling during daylight saving time on the mainland.

What to do if you miss the change or get confused

If you wake up and realize you forgot to change a clock, do not panic. Check your phone or a device you know updated correctly to see what time it actually is. Then adjust any manual clocks or devices you use regularly. If you are running late because of the confusion, text or call ahead to let people know.

If you are unsure whether your location observes daylight saving time, search online for your city or state name plus "daylight saving time." You can also call your local government office or check your employer's website — they usually send a reminder before the change happens.

If you have a recurring appointment or meeting scheduled for the day of the change, double-check the time with the provider or organizer. Some businesses adjust their hours or close early on the day clocks change, and you want to confirm you have the right time.

Frequently Asked Questions

Do I need to change my phone or computer clock manually?

No. Phones and computers connected to the internet update automatically. If your device does not update within an hour of the change, check that it is connected to Wi-Fi or your mobile network, or restart it. Older devices without internet access will not update on their own.

What time do clocks change, and do I lose or gain an hour?

Clocks change at 2 a.m. In March, you spring forward to 3 a.m., so you lose an hour of sleep. In November, you fall back to 1 a.m., so you gain an hour. Most people notice the March change more because they lose sleep.

Will my car automatically update to the new time?

Some newer cars with internet connectivity update automatically, but most do not. Check your car's manual or search your model number online to find the button or menu option to adjust the time manually. It usually takes less than a minute.

What if I live in a state that does not observe daylight saving time?

Hawaii, most of Arizona, and U.S. territories like Puerto Rico and Guam do not change their clocks. If you live in one of these places, your time stays the same on the dates when the rest of the country changes. If you travel to or from these places, remember the time difference shifts by an hour twice a year.

Can I adjust my sleep schedule before the time change?

Yes. A few days before the change, you can gradually shift your bedtime 15 minutes earlier (in March) or later (in November) to ease the adjustment. This works better for some people than waking up to a sudden one-hour shift, though most people adapt within a few days either way.