Most of the United States begins Daylight Saving Time at 2:00 a.m. on the second Sunday in March and reverts to standard time on the first Sunday in November. In the U.S., each time zone switches at a different time.

In the European Union, Summer Time begins and ends at 1:00 a.m. Universal Time (Greenwich Mean Time). It begins the last Sunday in March and ends the last Sunday in October. In the EU, all time zones change at the same moment.

Spring forward, Fall back

During DST, clocks are turned forward an hour, effectively moving an hour of daylight from the morning to the evening.

Principio del formulario

	United States			European Union
Year	DST Begins at 2 a.m.	DST Ends  at 2 a.m.		Summertime period begins at 1 a.m. UT	Summertime period ends at 1 a.m. UT
2012	March 11	November 4		March 25	October 28
2013	March 10	November 3		March 31	October 27
2014	March 9	November 2		March 30	October 26
2015	March 8	November 1		March 29	October 25
2016	March 13	November 6		March 27	October 30
2017	March 12	November 5		March 26	October 29
2018	March 11	November 4		March 25	October 28
	March 10	November 3		March 31	October 27
US calculator valid 1976-2099; EU 1996-2099. Change with up/down key.

Final del formulario

Spelling and grammar

The official spelling is Daylight Saving Time, not Daylight Saving Time.

Saving is used here as a verbal adjective (a participle). It modifies time and tells us more about its nature; namely, that it is characterized by the activity of saving daylight. It is a saving daylight kind of time. Because of this, it would be more accurate to refer to DST as daylight-saving time. Similar examples would be a mind-expanding book or a man-eating tiger. Saving is used in the same way as saving a ball game, rather than as a savings account.

Nevertheless, many people feel the word savings (with an 's') flows more mellifluously off the tongue. Daylight Savings Time is also in common usage, and can be found in dictionaries.

Adding to the confusion is that the phrase Daylight Saving Time is inaccurate, since no daylight is actually saved. Daylight Shifting Time would be better, and Daylight Time Shifting more accurate, but neither is politically desirable.

When in the morning?

In the U.S., clocks change at 2:00 a.m. local time. In spring, clocks spring forward from 1:59 a.m. to 3:00 a.m.; in fall, clocks fall back from 1:59 a.m. to 1:00 a.m. In the EU, clocks change at 1:00 a.m. Universal Time. In spring, clocks spring forward from 12:59 a.m. to 2:00 a.m.; in fall, clocks fall back from 1:59 a.m. to 1:00 a.m.

In the United States, Daylight Saving Time commences at 2:00 a.m. to minimize disruption. However, many states restrict bars from serving alcohol between 2:00 a.m. and 6:00 a.m. At 2:00 a.m. in the fall, however, the time switches back one hour. So, can bars serve alcohol for that additional hour? Some states claim that bars actually stop serving liquor at 1:59 a.m., so they have already stopped serving when the time reverts to Standard Time. Other states solve the problem by saying that liquor can be served until "two hours after midnight." In practice, however, many establishments stay open an extra hour in the fall.

In the U.S., 2:00 a.m. was originally chosen as the changeover time because it was practical and minimized disruption. Most people were at home and this was the time when the fewest trains were running. It is late enough to minimally affect bars and restaurants, and it prevents the day from switching to yesterday, which would be confusing. It is early enough that the entire continental U.S. switches by daybreak, and the changeover occurs before most early shift workers and early churchgoers are affected.

Some U.S. areas

For the U.S. and its territories, Daylight Saving Time is NOT observed in Hawaii, American Samoa, Guam, Puerto Rico, the Virgin Islands, the Commonwealth of Northern Mariana Islands, and Arizona. The Navajo Nation participates in the Daylight Saving Time policy, even in Arizona, due to its large size and location in three states.

A safety reminder

Many fire departments encourage people to change the batteries in their smoke detectors when they change their clocks because Daylight Saving Time provides a convenient reminder. "A working smoke detector more than doubles a person's chances of surviving a home fire," says William McNabb of the Troy Fire Department in Michigan. More than 90 percent of homes in the United States have smoke detectors, but one-third are estimated to have dead or missing batteries