Oct. 31 (UPI) -- Much of the United States will "fall back" early Sunday morning as daylight saving time ends, adding an hour of sleep for many in the pre-dawn hours.
The time change will mean the sun sets before 5 p.m. across the United States, as it now does in Hawaii and Arizona, which do not observe daylight saving time. The Navajo Nation, which mostly falls within Arizona's borders, does observe the time change.
Daylight saving time returns on the first Sunday in March 2021.
The bi-annual clock switching is not universally well-liked and has been contested in many states and the European Union over the years.
The time shift in the spring is correlated with drowsy driving and more fatal accidents.
Daylight saving time was most recently panned by the American Academy of Sleep Medicine, the largest scientific organization that studies sleep, which proposed replacing daylight saving time with a move to a year-round fixed time.
"Daylight saving time is less aligned with human circadian biology -- which, due to the impacts of the delayed natural light/dark cycle on human activity, could result in circadian misalignment, which has been associated in some studies with increased cardiovascular disease risk, metabolic syndrome and other health risks," the academy said this week.
The U.S. Department of Transportation oversees daylight saving time. The agency says moving the clocks forward and back reduces energy use from morning heating and evening air conditioning and cuts down on crime.