What is Daylight Saving Time?

Although there are some misconceptions about daylight saving time, the most common one is the name itself. Many people in the U.S., Canada, and Australia refer to it as "daylight savings time," which is incorrect, according to the U.S. Department of Energy. Officially, the name for turning the clock forward an hour in March is daylight saving time, using the singular version of the word “saving.” European countries refer to it as “summer time.”

In 1966, President Lyndon B. Johnson signed a law mandating that daylight saving time begin on the last Sunday in April and end on the last Sunday in October. Congress changed the law in 1986, requiring that daylight saving time began on the first Sunday in April. Then under the Energy Policy Act of 2005, Congress amended the law again, designating that daylight saving time would begin on the second Sunday of March at 2 a.m. and end at 2 a.m. on the first Sunday of November beginning in 2007. That law remains in effect today. In much of Western Europe, Summer Time begins on the last Sunday in March at 1 a.m. GMT and ends on the last Sunday of October at 1 a.m.

The U.S. government did not create daylight saving time to provide America’s farmers with additional daylight hours. The truth is, farmers were against the idea of daylight saving time when it started in 1918. The changeover caused significant interruptions in their harvesting and shipping schedules, as well as increases in their labor costs. American farmers and the agriculture industry led the fight to end daylight saving time in 1919, pressuring their government leaders to repeal the act.

Although many stories credit Benjamin Franklin for coming up with the initial idea of daylight saving time, it was actually George Hudson, an entomologist from New Zealand, who created the idea in 1895. He proposed a timeshift that would allow for two additional hours of sunlight in the summer so that he would have more time for studying insects. Then in 1905, William Willett proposed it to the British Parliament. Both Winston Churchill and Sir Arthur Conan Doyle backed Willett’s idea. He continued to pitch his idea to Parliament year after year, but they rejected the idea numerous times. Germany liked Willett’s idea, however, and was the first country to adopt it.

The U.S. adopted daylight saving time in 1918 at the end of World War 1 to "preserve daylight and provide standard time for the United States." The mandate started on March 31 and continued for the next seven months. However, in 1919, a large number of Americans pressured Congress to repeal it, including those in the agriculture industry. President Woodrow Wilson attempted to veto the repeal but was unsuccessful. President Franklin Delano Roosevelt enacted year-round daylight saving time during World War II, dubbing it “War Time.” It ended on September 30, 1945.

The purpose behind daylight saving time was to conserve energy and reduce electricity use in buildings, according to the Department of Energy. A study by the DOE in 2008 found that daylight saving time saved about 0.5 percent per day, totaling 1.3 billion kilowatt hours. However, there is more recent research showing that daylight saving time does not significantly reduce energy costs. Lights are now more efficient and are responsible for a smaller part of energy consumption.

Researchers have conducted numerous studies to investigate daylight saving and its effects on health. In 2014, a study published in the journal Open Heart concluded that heart attacks increased by 24 percent on the Monday following the daylight saving time switch in the spring. Several other studies found an increased risk of stroke on the Mondays and Tuesdays following the time change. Researchers also found that there are an increased number of car accidents as well as a higher number of on-the-job injuries on the first Monday following the “spring forward” time change for daylight saving time. Between 2002 and 2011, the impact resulted in more than 30 deaths, according to the American Economic Journal. Sleep deprivation and a lack of focus contribute to the accidents.

Studies show that robbery rates decrease once daylight saving takes effect. According to research by the Brookings Institution, the start of daylight saving time in the spring has coincided with a 7-percent drop in robberies over the entire day and a 27-percent decrease during the extra hour of sunlight in the evenings. The reason for this may be that many individuals end their work day around the time the sun is setting and daylight saving time allows workers to walk to their vehicles or into their homes while the sun is out. Criminals prefer to seek out victims in the dark. Congress enacted the four-week extension of daylight saving time, which resulted in fewer robberies and a $59 million savings in legal, medical, and investigative costs each year.

Businesses generally support daylight saving because the additional hours of sunlight encourage more consumer traffic. Retailers enjoy a higher volume of sales. Tourism, outdoor sports, and resort industries also benefit. More people perform home improvement projects during daylight saving time as well resulting in increased sales for those goods. Because people tend to leave their homes more to enjoy those extra hours of sunlight, they spend more on gasoline. The Chamber of Commerce, who works to promote small business and retailers, has been the most enthusiastic supporter of daylight saving time since 1915. However, television executives are not fans of it. TV ratings fall every year during the first week of the time change.

In the U.S., each state has the right to decide for themselves whether or not to participate in daylight saving. More than two dozen states have considered extending daylight savings time, but that requires federal approval. Hawaii is the only state in the U.S. which does not observe it. Most of Arizona doesn’t either, with the exception of the Navajo Nation. Additionally, American Samoa, Guam, Puerto Rico, the Virgin Islands and the Northern Mariana Islands do not move their clocks forward in the spring or back in the fall. In 2018, California voters approved year-round daylight saving time, which proponents expect to win federal approval. Some U.S. legislators have also proposed permanent daylight saving time resolutions for all states.