Washington (CNN) After losing an hour of executive time to "springing forward" his clock an hour over the weekend, President Donald Trump voiced his support Monday to eliminate states' legal requirement of "falling back" an hour each year.

"Making Daylight Saving Time permanent is O.K. with me!" Trump tweeted.

One of the most common justifications for the time switch is the presumption that by extending summer daylight later into the evening, Americans use less energy.

It was the reason Congress used in enacting Daylight Saving Time during World War I and again after the United States joined WWII, according to author David Prerau, who wrote a book which traced the history of the shift on Daylight Saving Time.

But a 2008 Department of Energy study found that daylight saving time reduces annual energy use by about 0.03%. And a study that same year from the University of California-Santa Barbara found it might even increase energy consumption.

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