Twice each year, millions of people change almost every clock they own before going to bed. Others forget and wake up confused when their clocks are out of sync. Once each year, many people go to work exhausted after losing an hour of sleep, and once each year, they enjoy an extra hour in bed. Here’s why.
Benjamin Franklin once humorously suggested people rise earlier to make better use of daylight, but the modern idea of changing clocks did not appear until 1916, more than 125 years after Dr. Franklin died.
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America’s Early Experiments
The United States temporarily adopted Daylight Saving Time in 1918. America was fighting World War I, and American leaders concluded that the additional hour of daylight would save fuel needed for the war effort. When the war ended, many Americans wanted to return to normal schedules, especially farmers who often worked by the position of the sun rather than by clocks. Although the national law ended after one year, many states continued to observe Daylight Saving Time on their own.
Congress set the clocks ahead again in 1942 during the Second World War and again during an energy shortage in 1973. The 1973 experiment was intended to be permanent, but several children were injured or killed in traffic accidents after leaving for school before the sun rose.
Modern Daylight Saving Time in the United States
In the United States, every state except Hawaii and most of Arizona observes Daylight Saving Time from the second Sunday in March to the first Sunday in November. Territories of the United States, including Puerto Rico, Guam, and the United States Virgin Islands, also choose not to observe Daylight Saving Time. Hawaii and the territories are closer to the equator than the other states, so the amount of daylight changes very little during the year. Summer temperatures in Arizona often rise above 100°, so Arizona lawmakers decided it made more sense to avoid extending hot summer evenings by an additional hour.
People often describe Daylight Saving Time with the expression ‘spring ahead and fall back.’ Clocks are moved ahead one hour in the spring and turned back one hour in the fall.
Most of Europe observes Daylight Saving Time, except for Iceland, Russia, and Belarus. Most of Australia and all of New Zealand also move their clocks forward during the summer months. Israel and Lebanon follow similar practices.
Changing clocks seasonally is unpopular with some people. The United States Congress has debated the issue for years. The European Union even voted in 2019 to phase out what Europeans call Summer Time, but member nations could not agree on whether to remain permanently on standard time or summer time, so Europeans and Americans continue to change their clocks.
Many sleep researchers oppose resetting clocks. They argue that time changes upset our circadian rhythms, the internal clock that helps us wake up at about the same time every day. Many researchers prefer permanent standard time rather than permanent Daylight Saving Time because winter sunrises would occur very late in the morning under permanent DST.
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Mr. Donn has an excellent website that includes a section on Geography.
Cite this page:
Dowling, Mike, “Daylight Saving Time: Spring Ahead, Fall Backward,” mrdowling.com, September 17, 2026. Web. [Date of access].
Sources:
Emergency Daylight Saving Time Energy Conservation Act of 1973 (Public Law 93-182)
Michael Downing, Spring Forward: The Annual Madness of Daylight Saving Time (Shoemaker & Hoard, 2005)
David Prerau, Seize the Daylight: The Curious and Contentious Story of Daylight Saving Time (Thunder’s Mouth Press, 2005)