On Sunday, Nov. 4, 2018 most Americans will set their clocks back an hour, as daylight saving time (sometimes called daylight savings time) comes to a close, and most of the United States will "lose" an hour of daylight. These spring and fall clock changes continue a long tradition started by Benjamin Franklin to conserve energy.
Why do we still have daylight saving time?
Fewer than 40 percent of the world's countries observe daylight saving time, according to timeanddate.com. However, those who do take advantage of the natural daylight in the evenings. That's because the days start to get longer as Earth moves from the winter season to spring and summer, with the longest day of the year on the summer solstice. During the summer, Earth, which revolves around its axis at an angle, is tilted directly toward the sun (at least its top half).
Regions farthest away from the equator and closer to the poles get the most benefit from the DST clock change, because there is a more dramatic change in sunlight throughout the seasons.
Research has also suggested that with more daylight in the evenings, there are fewer traffic accidents, as there are fewer cars on the road when it's dark outside. More daylight also could mean more outdoor exercise (or exercise at all) for full-time workers.
Myths and Interesting Facts
Turns out, people tend to have more heart attacks on the Monday following the "spring forward" switch to daylight saving time. Researchers reporting in 2014 in the journal Open Heart, found that heart attacks increased 24 percent on that Monday, compared with the daily average number for the weeks surrounding the start of DST.
Before the Uniform Time Act was passed in the United States, there was a period in which anyplace could or could not observe DST, leading to chaos. For instance, if one took a 35-mile bus ride from Moundsville, West Virginia, to Steubenville, Ohio, he or she would pass through no fewer than seven time changes, according to Prerau. At some point, Minneapolis and St. Paul were on different clocks.
A study published in 2009 in the Journal of Applied Psychology showed that during the week following the "spring forward" into DST, mine workers got 40 minutes less sleep and had 5.7 percent more workplace injuries than they did during any other days of the year.
Pets notice the time change, as well. Since humans set the routines for their fluffy loved ones, dogs and cats living indoors and even cows are disrupted when, say, you bring their food an hour late or come to milk them later than usual, according to Alison Holdhus-Small, a research assistant at CSIRO Livestock Industries, an Australia-based research and development organization.
The fact that the time changes at 2 a.m. at least in the U.S., may have to do with practicality. For instance, it's late enough that most people are home from outings and setting the clock back an hour won't switch the date to "yesterday." In addition, it's early enough not to affect early shift workers and early churchgoers, according to the WebExhibits, an online museum.