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

In March, clocks spring forward one hour at 2 a.m. local time. In November, clocks fall back one hour at 2 a.m. local time. This happens across most of the country, though Hawaii, most of Arizona, and some U.S. territories do not observe daylight saving time and keep the same time year-round.

The exact date shifts each year because it is tied to a calendar rule, not a fixed date. March's change always falls between March 8 and 14. November's change always falls between November 1 and 7. Knowing the rule — second Sunday in March, first Sunday in November — means you can figure out the date for any year without looking it up.

The time change affects clocks in your home, car, phone, and any device that does not update automatically. Phones and computers usually adjust themselves if they are connected to the internet. Older appliances, car clocks, and wall clocks require manual adjustment.

Key Takeaways

  • Clocks spring forward one hour on the second Sunday in March and fall back one hour on the first Sunday in November across most of the United States.
  • The change happens at 2 a.m. local time, which is why most people adjust clocks before bed the night before.
  • Hawaii, most of Arizona, and some U.S. territories do not change their clocks and stay on the same time year-round.
  • Smartphones and computers update automatically if connected to the internet, but older clocks and car dashboards need manual adjustment.
  • The week after the change, you may feel tired or off-schedule because your body's internal clock has not caught up yet.

Why the United States changes clocks

Daylight saving time was introduced to make better use of daylight hours during seasons when the sun rises and sets at different times. The idea is that by shifting an hour of daylight from morning to evening, people use less electricity for lighting in the evening hours.

The practice has been in place since World War I, though it was not permanent until 1966, when Congress passed the Uniform Time Act. That law allowed states to stay on standard time year-round if they chose, but required that any state observing daylight saving time follow the same dates nationwide. This is why most states change on the same days, even though the energy savings are debated by researchers.

Which devices update automatically and which do not

Smartphones, tablets, and computers connected to the internet update their clocks automatically through a time server. You do not need to do anything — the change happens in the background. The same is true for many modern televisions, smart home devices, and appliances with built-in clocks that connect to Wi-Fi.

Devices that do not connect to the internet require manual adjustment. This includes car dashboard clocks, wall clocks, alarm clocks, ovens, microwaves, and older watches. Some car models have a menu option to adjust the time; others require you to press buttons on the dashboard. Check your car's manual or the device itself for instructions.

If you have a smart home system like Alexa or Google Home, those devices usually update automatically. However, any device that relies on them for time — like a smart display — will also update. Older devices plugged into outlets but not connected to the internet will not change unless you adjust them manually.

How to prepare the night before the change

The easiest approach is to adjust clocks before you go to bed the night before the change. This way, when you wake up, your home is already on the correct time. Start with the clocks you use most: your bedroom alarm clock, kitchen clock, and car clock.

In March, when clocks spring forward, set them one hour ahead. In November, when clocks fall back, set them one hour behind. If you have many clocks, write down which ones need adjustment so you do not miss any. Microwave and oven clocks are straightforward to overlook but matter if you rely on them for cooking times.

For car clocks, check your owner's manual for the adjustment method. Some cars have a settings menu you navigate with steering wheel buttons; others have a small dial or button on the dashboard. If you cannot find it, the manual will tell you exactly where it is and how long it takes to change.

States and regions that do not change clocks

Hawaii and most of Arizona remain on the same time year-round and do not observe daylight saving time. Hawaii stays on Hawaii-Aleutian Standard Time. Arizona stays on Mountain Standard Time (though the Navajo Nation within Arizona does observe daylight saving time).

U.S. territories that do not change clocks include Puerto Rico, the U.S. Virgin Islands, Guam, American Samoa, and the Northern Mariana Islands. If you live in or travel to these places, you do not need to adjust clocks on the change dates.

A few counties in other states also do not observe daylight saving time, though this is rare. If you are unsure whether your area changes clocks, check your state's government website or ask your local utility company.

What to expect in the days after the change

Many people feel tired or groggy for a few days after the clock change because their body's internal rhythm — called the circadian rhythm — has not adjusted yet. This is more noticeable in March when you lose an hour of sleep, but some people feel it in November too, even though you gain an hour.

Your body uses light and darkness to regulate sleep and wakefulness. When the clock changes but the sun's schedule does not, there is a mismatch. It usually takes three to seven days for your body to adjust. Getting sunlight in the morning and keeping your bedroom dark at night can help your body adapt faster.

If you have young children or pets, they may also seem off-schedule for a few days. Sticking to your normal routine — eating meals and going to bed at the usual times — helps everyone adjust more quickly than trying to force an when ready change.

How to find the exact date for any year

You do not need to memorize the dates. The rule is straightforward: spring forward on the second Sunday in March, fall back on the first Sunday in November. Once you know this rule, you can figure out the date for any year by looking at a calendar.

Find March on the calendar and count the Sundays. The second one is your spring-forward date. Then find November and count the Sundays. The first one is your fall-back date. This works for every year, so you can plan ahead if you need to.

Most phones and computers display the correct date automatically, so you can also just check your device if you need to know the exact date quickly. Many people set a phone reminder a few days before the change so they do not forget to adjust their manual clocks.

Frequently Asked Questions

Do I need to adjust my phone or computer clock?

No. Phones and computers connected to the internet update automatically. If your device is not updating, check that it is connected to Wi-Fi or cellular data and that the automatic time setting is turned on in your settings. Older devices not connected to the internet will not update and need manual adjustment.

What time do clocks change, and do I adjust them before bed or in the morning?

Clocks change at 2 a.m. local time. Most people adjust them the night before so everything is correct when they wake up. You can adjust them in the morning instead, but doing it the night before is easier and less confusing.

Does daylight saving time happen on the same day everywhere in the world?

No. Different countries and regions change on different dates or do not observe daylight saving time at all. Europe changes on the last Sunday of March and October. If you work with people in other time zones, check their local rules during the week of the change.

Will my car's clock update automatically?

Most newer cars with connected systems update automatically. Older cars with manual dashboard clocks do not. Check your owner's manual for instructions on how to adjust your specific car's clock, as the method varies by model.

What should I do if I forget to change a clock?

If you forget to adjust a manual clock, just change it when you notice. There is no penalty or important date — you straightforward adjust it to the correct time. If it is a clock you use regularly, like an alarm clock or kitchen clock, adjust it as soon as you realize it is wrong.