When do we set our clocks back?

Be ready to set your clocks back at 2 a.m. Sunday. At 2 a.m., you will gain an hour, meaning clocks will “fall back” to 1 a.m. Clocks will stay that way until March 12. On that date, you will lose an hour at 2 a.m., meaning clocks will “spring ahead” to 3 a.m.

When and why did daylight saving time begin?

As far back as 1775, Benjamin Franklin raised the idea of getting up earlier to make better use of daylight and avoid nighttime burning of candles. Around the turn of the 20th century, George Hudson of New Zealand and William Willett of England separately pitched summertime clock changes, each seeking an extra hour of sunlight for personal hobbies. But daylight saving time wasn’t implemented until World War I, when countries on both sides of the conflict adopted it as a way of saving energy, according to David Prerau, author of “ Seize the Daylight: The Curious and Contentious Story of Daylight Saving Time .” The practice returned during World War II, and at the end of the war, parts of the United States didn’t want to give it up. So, time varied from town to town. Individual jurisdictions chose whether to keep daylight saving time and when to change the clocks, creating a chaotic patchwork system. In one example, Prerau said, there were seven time changes over a 35-mile bus ride from Steubenville, Ohio, to Moundsville, W.Va. “Thirty-five miles, seven changes of your watch if you want to keep in sync,” Prerau said. “That was a well-known, famous story at the time.” To put an end to the chaos, the Uniform Time Act of 1966 established set dates for daylight saving time. A state could choose to stick to year-round standard time, but had to do so statewide. For the vast majority of the country, changing the clocks is a twice-yearly ritual.

Where is daylight saving time observed?

Most of the United States spends 34 weeks, or about seven months from mid-March to mid-November, on daylight saving time. Hawaii, most of Arizona (with the exception of the Navajo Nation), and territories such as Puerto Rico, Guam, the U.S. Virgin Islands, the Northern Mariana Islands and American Samoa remain on standard time. (The Senate legislation would exempt these places from adopting permanent daylight saving time.) Around the world , most of North America, Europe and New Zealand as well as some parts of the Middle East, South Africa and Australia practice a biannual switch, but the dates of the time change vary. Much of Africa and Asia do not switch.

What are the pros and cons of daylight saving time and standard time?

Twice-yearly switching Changing the clocks twice a year (setting them ahead one hour in March to “spring forward” and back one hour in November to “fall back”) has become widely viewed by the public, lawmakers and sleep experts as not only an inconvenience, but also as a serious health and public safety concern. In 2020, the American Academy of Sleep Medicine issued a position statement calling for an end to the biannual time change. The AASM highlighted data showing that changing the clocks, particularly from standard time to daylight saving time in the spring, has been associated with increased risks in the following days of cardiovascular problems, including heart attacks and stroke , mood disorders , sleep issues , and motor vehicle crashes , among others. Daylight saving time While the original purpose of daylight saving time was to save energy by extending daylight into the evening, research has cast doubts on that idea. After Congress passed the Energy Policy Act in 2005, which extended daylight saving time by four weeks, studies and reports , including those produced by the Department of Energy , found that electricity savings during the extra weeks were relatively small. Additional studies suggest that while people might use less energy for certain purposes, such as lighting, they might use more energy for other purposes, such as cooling the air in the evenings. Energy aside, advocates of daylight saving time also argue that it promotes public safety, with evidence linking the extra daylight in the evenings to a decrease in crime . And retailers and many outdoor industries have supported daylight saving time , suggesting that people are more likely to shop or participate in outdoor activities during the extra daylight hours. But sleep experts say that those in favor of more light later in the day may not be considering the difficulties associated with waking up in the dark and the fact that evening light can adversely affect the body’s ability to fall asleep by suppressing melatonin. They say permanent daylight saving time could put people at risk of a condition known as “social jet lag,” or the chronic misalignment between the timing of the demands of work, school or other obligations and our innate circadian rhythm, which is strongly tied to sunlight. This misalignment has been associated with adverse effects on cognition and mood as well as increased risks of obesity, metabolic syndrome, cardiovascular disease and depression. Another concern about permanent daylight saving time is that more dark mornings could affect the safety of children walking or being bused to school. Standard time Standard time in many places is not conducive to more active spring and summer evenings. But many sleep experts prefer it because it is best aligned with humans’ intrinsic circadian rhythm. The earlier daylight of standard time provides a critical cue for the body’s biological clocks. And when darkness falls earlier in the evening, it helps signal the body that it’s time to wind down and prepare for sleep. Sleep experts are not the only people in favor of standard time; the AASM’s position statement on eliminating daylight saving time also received support from the National Safety Council and the National PTA, among other groups.

What happened the last time the U.S. tried permanent daylight saving time?

Congress voted to shift the country to year-round daylight saving time in January 1974, during the energy crisis caused by the oil embargo imposed by the Organization of Arab Petroleum Exporting Countries. Polling showed that most Americans supported the measure, which was signed into law by President Richard M. Nixon. It was supposed to continue until April 1975. But the change soon proved unpopular with the public. Most Americans had to head to school and work in the dark that winter, with sunrise arriving around 8:30 a.m. in cities including D.C. and New York, and 9 a.m. in Detroit and Indianapolis. “If you think about a 9 a.m. sunrise, almost everyone goes to work or school before the sunrise,” Prerau said. “And not only, by the way, is it darker, but it’s winter, and so it’s colder.” Disapproval of the switch grew when multiple children were struck by cars while headed to school in the dark. By late January, the governor of Florida had called for a repeal. By February, some members of Congress — including one of the bill’s co-authors — were questioning their decision. Government studies estimated about 100,300 barrels of oil were saved per day between January and April. But public displeasure was overwhelming. On Oct. 6, not long after Nixon’s resignation, President Gerald Ford signed a bill ending the permanent daylight saving time experiment.

Where do today’s lawmakers stand?

Although states can choose to adopt permanent standard time, they cannot institute permanent daylight saving time without approval from Congress. More than 40 states, including Maryland , are considering bills to end switching, pending federal legislation. The Senate’s recent move to unanimously pass the Sunshine Protection Act , legislation pushed by Sen. Marco Rubio (R-Fla.) since 2018, could be the game changer. The swift passage, which happened with little discussion , appeared to come as a surprise to many, including some senators , as The Washington Post’s Paul Kane wrote. The Senate action came just days after the pros and cons of the time systems — biannual switching, daylight saving time and standard time — were debated during a hearing held by a House Energy and Commerce subcommittee .

Does the public want to abolish daylight saving time?

More than 60 percent of Americans are in favor of stopping the biannual switch, according to a November Economist/YouGov poll . Of the people who want to eliminate the shift, nearly twice as many prefer permanent daylight saving time over standard time. The poll found that older adults expressed a clear preference for year-round daylight saving time while adults under 30 were “closely divided” on whether they want more daylight in the morning or later in the evening. These results somewhat differ from a 2019 AP-NORC poll , which showed that while Americans generally didn’t want to keep switching, 40 percent were in favor of permanent standard time compared with 31 percent who wanted daylight saving time. Andrea Salcedo contributed to this report.

Daylight saving time: Explaining the century-old debate

By Allyson Chiu

and

Brittany Shammas

Updated November 2, 2022 at 5:20 p.m. EDT|Published March 18, 2022 at 10:00 a.m. EDT

The prospect of adopting year-round daylight saving time has reignited fierce debate: While most Americans agree that the switch must end, there is strong disagreement over whether clocks should be set permanently to daylight saving time or standard time. (iStock)

For decades, many Americans have muddled through twice-yearly time changes as much of the country toggled between standard time and daylight saving time. But the confusing and often disruptive biannual practice, which has been associated with adverse effects on health and public safety, may become a relic of the past.

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On March 15, the Senate unanimously passed legislation that would eliminate switching and make daylight saving time permanent. The bipartisan bill, which would take effect next year, must be passed by the House of Representatives and signed by President Biden before it becomes law. Still, the prospect of adopting year-round daylight saving time has reignited fierce debate: While most Americans agree that the switch should end, there is strong disagreement over whether clocks should be set permanently to daylight saving time or standard time.

Why daylight saving time is worse for your body than standard time

Below, we’ve compiled answers to commonly asked questions about daylight saving time; the information in this FAQ will be updated as developments occur.

Daylight saving time

Snoozed: A bill to permanently “spring forward” has been stalled in Congress for more than seven months, as lawmakers trade jabs over whether the Senate should have passed the legislation at all.

Sleep experts say the Senate has it wrong: Experts widely agree with the Senate that the country should abandon its twice-yearly seasonal time changes. However, many experts believe the country should adopt year-round standard time.

The science of changing our clocks: Daylight saving time may have given us more time to enjoy late-time summer activities, but it can have a negative impact on our health. Here’s how your brain and health are affected by time changes.

Is the grass greener on the other side?: We tend to think about daylight saving time as giving us more sunlight in the evening hours (it does), but standard time also has benefits too: the Sun is up when you wake in winter. Explore how sunrise and sunset would change if permanent daylight saving time is passed.

America’s clock craziness: For roughly two decades, nobody had any clue what time it was, with some localities observing daylight saving, some not — until President Lyndon B. Johnson signed the Uniform Time Act in 1966.