12 Surpising Facts About

Daylight Saving Time

1. The length of daylight savings has changed more than once.

DST originally started in April and ended in October, but the Energy Policy Act of 2005 extended DST by 4 weeks. For daylight savings time 2023, Americans will set their clocks forward on March 12 and back on November 5.

2. Not all U.S. states and  territories observe DST.

Hawaii and most of Arizona do not observe DST. Neither do most U.S. territories, including Puerto Rico, Guam, American Samoa, the Northern Mariana Islands, and the U.S. Virgin Islands.

3. Some say daylight savings time killed the drive-in movie theater.

A consortium of drive-in movie theater owners bitterly opposed the adoption of DST in 1966. Today, only about 320 remain, and many enthusiasts say that DST is at least partly to blame.

4. DST exacerbates sleep deprivation.

It can take weeks for sleep cycles to adapt to DST, and kids have a particularly hard time adjusting to new sleep patterns. Some studies link the lack of sleep at the start of DST to, depression, suicide, and even risk of stroke and miscarriages.

5. It also causes more car accidents.

According to a 2020 study, spring daylight saving time "significantly increased fatal motor vehicle accident risk by 6 percent" and that the ""MVA risk increase waned in the week subsequent to DST."

6. Heart attacks are more common on Monday after daylight savings.

A 2014 study by the University of Michigan Frankel Cardiovascular Center shows a 24 percent jump in the number of heart attacks on the Monday after DST compared with other Mondays throughout the year.

7. DST doesn't actually save energy.

Daylight saving time was designed to help consumers rely less on artificial light, which should in theory save electricity. Today, however, the widespread use of air conditioners, computers, and TVs has virtually wiped out that energy savings.

8. Most Americans aren't really on board with daylight savings.

Regardless of where they live, about 6 in 10 Americans would like to do away with clock changes. Most prefer the later year-round hours of DST, and about 13 percent want permanent earlier hours.

9. With more daylight in the evenings, shoppers spend more.

Malls, independent retailers, and companies in the sports, leisure, and tourism industries were early proponents of DST and continue to support it today.

10. Farmers are opposed to DST.

Dairy farmers in particular have been vociferously opposed, because cows are sensitive to milking times. Further, many farmers prefer more outdoor work time in the morning rather than the early evening, especially in hot climates.

11. Sleep experts support  year-round standard time.

Doctors note that the light/dark cycle is key to circadian rhythm and switching to permanent standard time best aligns with our biology and sleep health.

12. The Sunshine Protection Act could make DST permanent.

In March 2022, the U.S. Senate unanimously passed the Sunshine Protection Act, which would make daylight saving time permanent—no more changing clocks. Although it stipulates a November 2023 start date, as of March 2023 it still has not passed the House.

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