When and How to Change Your Clocks for Daylight Saving Time

Daylight saving time changes from year to year

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 Dan Burn-Forti/Stone/Getty Images

Each year, the exact dates for instituting and ending daylight saving time change, but in the United States, it begins at 2 a.m. on the second Sunday of March and ends at 2 a.m. on the first Sunday of November. The concept was designed to extend daylight later into the evening during the summer months by pushing clocks forward during that part of the year, usually by one hour. With the exception of countries near the equator, most nations of the world have used some form of daylight saving time or have done so in the past.

When to Change Your Clocks

It's easy to remember which way to change the clock by remembering that you "spring forward" in the spring and "fall back" in the fall. Specifically, this means you reset your clocks from 2 a.m. to 3 a.m. when daylight saving time begins and reset them from 2 a.m. to 1 a.m. when it ends.

This chart provides beginning and ending dates for daylight saving time through 2032.

Daylight Saving Time Calendar Dates
YearBeginsEnds
2019March 10November 3
2020March 8November 1
2021March 14November 7
2022March 13November 6
2023March 12November 5
2024March 10November 3
2025March 9November 2
2026March 8November 1
2027March 14November 7
2028March 12November 5
2029March 11November 4
2030March 10November 3
2031March 9November 2
2032March 14November 7

Why do we have daylight saving time?

Benjamin Franklin first broached the subject of moving clocks to take advantage of summer daylight in a 1784 essay.

The idea did not take hold, though, until World War I, beginning with Germany's efforts to save fuel by moving clocks ahead one hour. The logic was that the more daylight people had later into the evening, the less energy they would need to use for artificial light.

The idea spread throughout Europe, and the U.S. enacted a law in 1918 that established daylight saving time in addition to standardizing time zones.

During World War II, the U.S. expanded daylight saving time to the full year. Then, after the conclusion of the war, there was no federal law, and states and local municipalities could make their own decisions to observe daylight saving time or not. This, not surprisingly, wreaked havoc with transportation schedules, broadcast schedules, and more, leading to a federal standard again being adopted in 1966.

States still can be exempt from the law if their legislatures pass a law choosing not to follow daylight saving time. As of 2018, Arizona and Hawaii do not observe daylight saving time.

Why 2 a.m.?

Changing clocks at 2 a.m. might seem like a strange and arbitrary time, but there is a logical argument for why that time was chosen. It's an hour with a limited number of activities that would be impacted during the time clocks are changed. Most businesses are closed, and even bus and train schedules have minimal demand at that hour. Additionally, using 2 a.m. as the designated time prevents the confusion of a time change that would shift back to the previous day.

Regardless, few people actually change their clocks at precisely 2 a.m. Most people switch their clocks before they go to bed the night before the change.

Increasingly, technology is making it so that people don't have to do anything to change clocks. While some clocks certainly still need to be changed manually, computers, cell phones, smart watches, cars, and appliances all can be programmed to make the change automatically at the appropriate time.

Opposition

Though it has become an accepted practice, daylight saving time still has its share of critics. Farmers, in particular, generally start their day based on when the sun rises, which happens later in the day—according to the clock—when daylight saving time is in effect. In an article on webexhibits.org, a farmer notes that his livestock does not recognize that it is supposed to be an hour later or an hour earlier.

Parents of schoolchildren also have been frequent critics of daylight saving time because it reduces available daylight in the morning at the beginning and at the end of the school year.

This means children often are expected to walk to school or to bus stops during times of heavy traffic when it still is dark outside.

Sometimes, daylight saving time leads to confusion that can have consequences ranging from disastrous to amusing. In 1999, three Palestinian terrorists presumably blew themselves up because their targets in Israel had changed their clocks for the winter. Not realizing the difference in time led to the bombs detonating while they still were being transported to their destinations. On the lighter side, the time change can create inconsistencies with the birth certificates of twins if one is born just before clocks are pushed back and the other is born after they are set back. For example, if a twin is born 1 minute before clocks are to be set back, and the other twin is born 15 minutes later, after clocks had been set back, the birth certificates would indicate that the first twin was born at 1:59 a.m. while the younger twin was born at 1:14 a.m.

How much money is saved by daylight saving time?

There is little agreement on how much—if any—money is saved by daylight saving time. A study done to measure the financial impact in Indiana after it adopted daylight saving time concluded that changing clocks actually had the opposite effect of the one intended. While people did use less artificial light, they spent more on heating and cooling, resulting in an overall increase in energy usage of 1 percent. In the warmest summer months, people used their air conditioning longer into the evening, and in the cooler spring and fall months, they used their heat more in the darker mornings.

While it is arguable that daylight saving time benefits tourism and other industries that profit from recreational activities, Forbes notes that television ratings take a hit because people are outside longer as opposed to inside watching their favorite programs.

A 2012 paper in the Journal of Applied Psychology even argued that daylight saving time had a negative impact on productivity because it increased cyberloafing, when employees surf the internet instead of working. The authors argued that daylight saving time has a negative impact on sleep habits and patterns, and that the lack of quality sleep leads to increased cyberloafing.