Daylight saving time ends Sunday at 2 a.m., when clocks will "fall back" one hour. That gives us all an extra hour of sleep -- or activity -- but it also means nightfall comes an hour earlier until March, when DST starts up all over again.
Last March, the the Sunshine Protection Act, which would enact daylight saving time permanently.
"The biannual transition of 'spring forward' and 'fall back' disrupts circadian sleeping patterns, causing confusion, sleep disturbances and even an elevated risk to heart health," Sen. Marco Rubio, who reintroduced the bill in 2021, said at the time.
Rubio claimed that permanent daylight saving time would improve productivity and health and decrease seasonal depression, childhood obesity and automobile accidents.
For now, the Sunshine Protection Act has stalled in the House. Many states have passed legislation extending DST, but they must wait for Congress to make its move first.
Here's everything you need to know about daylight saving time, including why we have it, why some people hate it and where efforts to make it permanent are headed.
For more on the time change, learn how to and recognize the symptoms .
What is daylight saving time?
In the US, the advancing of the clocks one hour in spring was first formally adopted in 1918 with the Standard Time Act. But that measure was abolished shortly after World War I.
It was reintroduced by President Franklin Roosevelt in 1942, after the US entered World War II, and remained in place until 1945.
Post-WWII, various municipalities made their own decisions about observing daylight saving time, which made travel timetables and other scheduling a nightmare. The Uniform Time Act of 1966 established a standard daylight saving time period nationwide, beginning at 2 a.m. on the last Sunday in April.
In response to an OPEC oil embargo, President Richard Nixon signed a bill in 1974 putting the US on permanent daylight saving time for two years. But as the Watergate scandal became more public, support for Nixon -- and the plan -- dwindled quickly. Days after his resignation, and just eight months after the full-time DST plan was instituted, an amendment was introduced to repeal it.
Daylight saving time moved up three weeks in 2005: Currently, it begins at 2 a.m. on the second Sunday in March, when clocks advance, or "spring forward," one hour. They are then rewound, or "fall back," an hour, returning to standard time on the first Sunday in November.
DST isn't observed in Asia, Africa or many countries closer to the equator, where the change in sunrise and sunset doesn't vary much throughout the year.
Two US states -- Hawaii and Arizona -- also don't observe daylight saving time -- nor do Puerto Rico, the Virgin Islands, American Samoa, Guam or the Northern Mariana Islands.
Why make daylight saving time permanent?
Changing clocks twice a year robs Americans of sleep and productivity and causes scheduling errors and other issues. A 2016 study by workforce consultant Chmura Economics and Analytics estimated that the biannual switchover costs the US more than $430 million a year.
Advocates point to studies showing car accidents involving pedestrians and wildlife decrease during daylight saving months. And the additional daylight can have other effects, too -- such as reducing the number of robberies by 27%, according to the Brookings Institution.
Rubio also argued more sunlight would provide more opportunities for physical exercise.
"We desperately want our kids to be outside, to be playing, to be doing sports, not just to be sitting in front of a TV or a computer terminal or playing video games all day," Rubio said. "If you don't have a park or an outdoor facility with lights, you're basically shut down around 5 p.m. -- in some cases as early as four or 4:30 p.m."
The return to standard time offers Americans an extra hour of sleep, but since sunset comes earlier it can also triggera form of depression that can manifest as lethargy, an inability to concentrate and changes in eating and sleeping habits.
There's also an economic boost with DST, according to the US Chamber of Commerce, which claims Americans shop more after work if it's light out. According to JP Morgan Chase, there is a drop in economic activity of up to 5% when clocks return to standard time.
Wildlife would benefit, too, according to a new study in the journal Current Biology that found drivers would kill 37,000 fewer deer annually with year-round DST.
Why are some people for permanent standard time?
Many complaints about DST involve the inconvenience and cost of switching the clocks back and forth, as well as the risks of impaired focus and judgment from changing sleep schedules. Heart attacks spike by nearly a quarter in the days following the start of DST, according to a 2014 University of Michigan report. And fatal car accidents jump by 6%, according to a University of Colorado study.
But the American Academy of Sleep Medicine argued in a 2020 study that permanent standard time "most closely match[es] our circadian sleep-wake cycle."
"Daylight saving time results in more darkness in the morning and more light in the evening, disrupting the body's natural rhythm," wrote lead author M. Adeel Rishi.
"Standard time provides a better opportunity to get the right duration of high-quality, restful sleep on a regular basis," AASM President Jennifer Martin said in a statement, "which improves our cognition, mood, cardiovascular health, and overall well-being."
Parent groups have also argued that operating on daylight saving time means students are often heading to school before the sun has risen, increasing the risk of accidents.
What's next for the Sunshine Protection Act?
The House still has to vote on the bill and the odds of it being brought to a vote anytime soon are slim, especially after the midterm elections.
"We haven't been able to find consensus in the House on this yet," Rep. Frank Pallone, chair of the House Energy and Commerce Committee that oversees daylight saving time, told The Washington Post. "We don't want to make a hasty change and then have it reversed several years later after public opinion turns against it -- which is exactly what happened in the early 1970s."
Nineteen states -- Alabama, California, Colorado, Delaware, Florida, Idaho, Georgia, Louisiana, Maine, Minnesota, Mississippi, Montana, Ohio, Oregon, South Carolina, Tennessee, Utah, Washington and Wyoming -- have passed legislation or resolutions to stay on daylight saving time permanently -- if and when Congress allows it.
In addition, Massachusetts and Maine have commissioned studies on year-round DST.
Should it ever pass, the Sunshine Protection Act has a provision delaying its implementation to give airlines and other transport industries time to adjust their schedules.