For most of the United States, this weekend sees the return of clock confusion—and heated debate.
Many Americans will spring forward an hour to mark the beginning of daylight savings time (DST)—also known as daylight saving time—at 2 a.m. on Sunday, March 8. Time will fall back to standard time again on Sunday, November 1, when DST ends.
The annual adventure in altered timekeeping has produced some entertaining and exasperating situations over the past century. (Related: "Time to Move On? The Case Against Daylight Saving Time.")
Here are some strange-but-true facts you might not know about daylight savings time.
Cities Once Kept Their Own Time
Each U.S. state and territory is free to ignore daylight savings time, so residents of Arizona (except those on the Navajo Nation), Hawaii, Puerto Rico, the Virgin Islands, and other territories won't move their clocks this weekend.
If these exceptions seem confusing, the situation was far worse 50 years ago, according to Tufts University professor Michael Downing, author of Spring Forward: The Annual Madness of Daylight Saving Time. Before the U.S. Uniform Time Act of 1966, DST was often observed very locally—and chaos was the result.
"In 1965 there were 130 cities in the country with populations of 100,000 or more," Downing explained. "Fifty-nine did not observe daylight saving.
"Of the 71 that did, there were at least 20 different adoption dates. In Minnesota, St. Paul was on one time, Minneapolis was on a different time, and Duluth was on Wisconsin time. In fact, somebody even found a Minneapolis office building in which the different floors of the building were observing different time zones because they were the offices of different counties."
Things were so confused that in 1965 the director of the U.S. Naval Observatory, the country's center for strategic timekeeping, announced that the dissent over DST had made the world's greatest economic and military superpower the world's worst timekeeper, Downing noted.
Daylight Savings Was Based on Assumptions
Why did this tempest of timekeeping confusion begin in the first place?
Daylight savings time was first realized on a grand scale during World War I. It started in Germany, then caught on in a number of nations that wanted to reduce lighting demand and save coal for the war effort. During WWII, the U.S. observed year-round DST for the same reasons.
But it turns out that these sweeping time changes—mostly intended to save energy—weren't based on any evidence. (Related: "Extended Daylight Saving Time Not an Energy Saver?")
"We've all obeyed this dictum for a hundred years, and ... no one can really explain why," Downing said, adding that the first real attempt to quantify the supposed energy savings of DST occurred in 1966.
Governments Don't Get it Either
Governments have had just as much trouble keeping track of time changes as everyone else.
When Yugoslavia's president, Marshal Tito, visited the U.S. in 1963, his welcome was botched because of daylight savings time, Downing reported. "Tito's plane landed in a Virginia town that hadn't advanced its clocks with the rest of the state, so nobody was there to greet him."
"That same year, Pentagon officials were two hours late for an important military conference in Alaska because no one knew what time it was out there on the Russian border," Downing added. (See "Permanent Daylight Saving Time? Might Boost Tourism, Efficiency.")
Russia has had its own issues with managing DST, as have most other nations.
The Soviet Union first observed daylight savings time in the spring of 1930 after an edict by Josef Stalin. For some reason, however, the Soviet Union never turned the clocks back in the fall of that year.
"So for the duration of World War II, and the much longer Cold War, nobody really had an accurate sense of what time it was in Russia," Downing said.
Dirty Secret: We Like DST
Last year an opinion poll on DST taken by the Utah Governor's Office of Economic Development produced almost 14,000 written comments—a total volume nearly equal to the length of War and Peace.
"The strong, repetitive drumbeat in those comments was convenience," explained the development office's Michael O'Malley. "Many people don't want to move their clocks, whether it's backwards, forwards, or sideways. They just want to pick a time and stick with it."
Despite an apparent dislike of daylight savings, actions speak louder than words.
Downing noted that although countries like the U.S. and Great Britain instituted year-round DST at times, as during WWII, they still haven't succeeded in eliminating the changing of the clocks. (Also see "'Leap Second' to Be Added to the Weekend.")
"In the spring, people's fingers get itchy, and without fail they have moved the clocks to adopt a double daylight saving time by moving it an extra hour ahead, or just gone back to the regular old plan.
"I think people have come to believe and been converted to the idea that we are owed an extra hour of evening light in the spring," he added.
As proof, he notes that while many cities and states have petitioned for time zone changes over the years, 95 percent of such petitions have been for a movement to the eastern time zone—essentially the adoption of daylight savings time.
TV Networks Lose, Golf Courses Win
Daylight savings time has some unexpected winners and losers when it comes to how Americans spend their time and money.
Research shows that given an extra hour of evening daylight, many Americans use the time to go out and do things rather than watch the television shows they'd normally view at that time.
Nielsen ratings during the hours impacted by the change show large declines during the first week of DST—as much as 10 to 15 percent, even for popular shows.
"If the sun sets at 7:00, then more people are inside at 7:00. If it sets at 8:00, more people are inside at 8:00," said David Prerau, author of the book Seize the Daylight: The Curious and Contentious Story of Daylight Saving Time.
"They are still going to watch some TV, they are just going to watch it later."
Theaters also take a hit, Prerau added. "When it's dark early, people may feel it's a good night to take in a play or a movie. But when it's going to be light until 8:00, they may decide to take a walk or do something outside."
That means recreational facilities from golf courses to garden supply centers see a spike when DST begins.
"That hour of evening light might make the difference whether somebody feels they have the time to go out and play tennis or start a garden, or whether they don't," Prerau said.
Criminals Hate Daylight Savings Time
Thieves tend to do their dirty work under the cover of darkness. So creating an extra hour of evening light helps people get home during daylight hours, which appears to drop crime rates dramatically.
A 2012 study examined crime rates during the three weeks preceding and following the spring move onto DST.
During the extra hour of evening daylight, robberies decreased by 40 percent, according to data from the National Incident-Based Reporting System. Murder and rape rates also went down, though it's hard to say how much because the exact time such crimes are committed is often unknown.
The extra hour of light during the morning hours produced no increase in crime. "These types of crimes are just rare in the mornings, so the earlier hour of daylight has no impact in terms of rising crime rates," Prerau added.
Evening crime rates rose again, research showed, when daylight savings time ended.
Farmers Aren't Fans
Farmers have long been labeled as big backers of daylight savings time, or even credited with getting the practice going. Whether this idea came from farmers' early rising habits or some other reason, it's a myth.
"From the very beginning, when DST was proposed in Britain's Parliament in 1908, until today, farmers have been the number one group against daylight saving time," said Prerau.
Traditionally, farmers have set their schedule by the sun, and that's mostly still the case. But when the rest of society shifts an hour of light out of the morning hours, farmers have less daylight to handle morning tasks like getting their wares to market. Those charged with handling livestock like dairy cows say it's difficult for the clock-averse animals to adjust.
U.S. farmers don't put up the same kind of organized opposition to DST that they once did, but across the world, farmers are still the first group that would like to see the practice end, Prerau said.
"In fact, right now there is an ongoing fight in Queensland, Australia, where there was actually a daylight saving political party," he noted.
"People on the coast, which is primarily a resort economy, want the extra daylight in the evening, but the people living in the outback are mostly farmers and they don't want to observe daylight saving."