Why Do We “Spring Forward” But “Fall Back” With Daylight Saving Time?

This content was created by the National Sleep Foundation


Myths, truths, and debates about switching the clocks

The terms “spring forward” and “fall back” are used to describe a practice of changing standard time with the intention of  “saving” (as in, making better use of) natural light. During daylight savings time (DST), clocks are turned ahead one hour, so that the sun rises later in the morning and sets later in the evening. The change is reversed in autumn.

Originally enacted in the United States as a wartime conservation effort, observance of DST became federal law in 1918. (To dispel a common myth: It was not enacted for farmers—in fact, most farmers fought for its repeal.) While it was quickly repealed after the war ended, DST was observed nationally again during World War II. By 1966, some 100 million Americans were practicing some type of DST through their own local laws. In 1966, Congress acted to end the confusion and establish one consistent nationwide pattern. The Uniform Time Act of 1966 stated that DST would begin on the last Sunday of April and end on the last Sunday of October. (Any area that wanted to be exempt from DST could do so by passing a local ordinance. Hawaii and most of Arizona, for example, are exempt from DST.) By 2005, the Energy Policy Act established that DST begins each year on the second Sunday in March at 2:00am and that the changeover back to standard time (ST) occurs on the first Sunday in November at 2:00am.

How much difference can an hour make? Opinions about the 60-minute swap tend to be passionate. For instance, proponents say that DST saves energy because in the spring and summer months, more people may be outside in the evening and not using energy (in the form of artificial light) at home. Some simply relish long summer evenings full of outdoor barbecues, swims, and late sunsets. Opponents say that any energy savings due to using less artificial light have been offset by an increased use of air-conditioning over the past few decades. They also argue that the drawbacks of springing ahead include increased sleep debt, lost productivity, and a rise in traffic accidents due to drowsy driving during the first few days after the spring time change. Sadly, those traffic accidents can even include cars and bus drivers hitting young students who are walking to their bus stops or standing at them during the dark, early morning hours in the late spring and early fall.

Clearly, over the past century or so, the U.S. has had conflicting views about the usefulness of DST. Will DST be around forever? Only time will tell.

Not sure how to maximize efficiency during DST? Here are some tips on how to handle the time change.