What time does daylight saving time start? What is it? When to 'spring forward' this weekend

This Sunday, the majority of Americans will "spring forward" and set their clocks ahead an hour, losing an hour of sleep as the annual tradition of daylight saving time begins for the year.

Daylight saving time will end for 2024 in November, when we set our clocks back and gain an extra hour of sleep.

The time adjustment affects the daily lives of hundreds of millions of Americans, prompting clock changes, contributing to less sleep in the days following and, of course, later sunsets.

Those disruptions may have contributed to public sentiment souring on the time change in recent years, but legislative moves to do away with daylight saving time have stalled in Congress.

Even ahead of the time change on Sunday, there are already cities in every continental U.S. time zone that are reporting sunset times after 6 p.m. as the Earth and the Northern Hemisphere begins its tilt toward the sun and summer approaches.

Here's everything you need to know about the start of daylight saving time.

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What is daylight saving time?

Daylight saving time is the time between March and November when most Americans adjust their clocks by one hour.

We lose an hour in March (as opposed to gaining an hour in the fall) to accommodate for more daylight in the summer evenings. When we "fall back" in November, it's to add more daylight in the mornings. In the Northern Hemisphere, the vernal equinox is March 19, marking the start of the spring season. 

When does daylight saving time begin in 2024?

Daylight saving time will begin for 2024 on Sunday, March 10 at 2 a.m. local time, when our clocks will move forward an hour, part of the twice-annual time change that affects most, but not all, Americans.

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When does daylight saving time end in 2024?

Daylight saving time will end for the year at 2 a.m. local time on Sunday, Nov. 3, when we "fall back" and gain an extra hour of sleep.

Next year, it will begin again on Sunday, March 9, 2025.

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Is daylight saving time ending permanently?

The push to stop changing clocks was put before Congress in the last couple of years, when the U.S. Senate unanimously approved the Sunshine Protection Act in 2022, a bill that would make daylight saving time permanent.

Although the Sunshine Protection Act was passed unanimously by the Senate in 2022, it did not pass in the U.S. House of Representatives and was not signed into law by President Joe Biden.

A 2023 version of the act remained idle in Congress as well.

Does every state observe daylight saving time?

Not all states and U.S. territories participate in daylight saving time.

Hawaii and Arizona (with the exception of the Navajo Nation) do not observe daylight saving time. Because of its desert climate, Arizona doesn't follow daylight saving time. After most of the U.S. adopted the Uniform Time Act, the state figured that there wasn't a good reason to adjust clocks to make sunset occur an hour later during the hottest months of the year.

There are also five other U.S. territories that do not participate, either:

• American Samoa
• Guam
• Northern Mariana Islands
• Puerto Rico 
•  U.S. Virgin Islands 

The Navajo Nation, which spans Arizona, Utah and New Mexico, does follow daylight saving time.

Hawaii is the other state that does not observe daylight saving time. Because of its proximity to the equator, there is not a lot of variance between hours of daylight during the year.