Daylight Saving Time will begin March 14. Clocks move forward one hour at 2 a.m. the second Sunday of March, then, at 2 a.m. the first Sunday of November, the clocks are turned back an hour.

Twice a year, clocks around the world move forward or backward by an hour — spring forward, fall back.

DST is a systemto reduce electricity usage by extending daylight hours. For eight months out of the year, the US and dozens of other countries follow DST, and for the remaining four months, revert back to standard time in order to take full advantage of the sunlight. It isn’t Daylight Savings Time, though, it’s Daylight Saving Time.

More than one billion people in some 70 countries are affected by Daylight Saving Time each year. The only states that do not observe DST are Hawaii and most of Arizona. The U.S. possessions of Guam, Puerto Rico, the U.S. Virgin Island and American Samoa are also on standard time year-round. Since 2007, the U.S. has observed Daylight Saving Time from the second Sunday in March until the first Sunday in November.

As noted in the movie, “National Treasure,” Benjamin Franklin first had the idea of waking earlier to take advantage of the sunlight. Franklin was serving as a minister to France in 1784 when he sent a letter to the Journal of Paris, humorously describing how he was awakened by a loud noise one April morning, several hours earlier than his normal noon rising, and was astonished to see his room full of light yet with no candles or lamps burning. He went on to suggest that all Parisians rise seven hours earlier in the morning, and thus go to bed earlier in the evening, to decrease the hours of darkness that people were awake and would need to use candles. Franklin estimated this would save Paris residents 64,050,000 pounds of tallow and wax for half a year.

Germany was the first country to adopt Daylight Saving Time (DST) during World War I, and Britain quickly followed suit when Parliament established British Summer Time in 1916. In 1918, the U.S. Congress put the entire country on Daylight Saving Time for the duration of the war. This allowed people to spend more time operating by daylight rather than artificial light, which saved precious fuel. after the War ended, and Congress repealed the national law, some local areas observed Daylight Saving Time on their own schedules.

When World War II began, Congress quickly re-instituted year-round Daylight Saving Time (DST), which lasted until Sept. 30, 1945.

The Uniform Time Act of 1966 established standard dates for DST beginning the last Sunday in April and ending the last Sunday in October. Observation of the time change was not mandated, but if a state or locality wanted to make the change had to do so on the dates set by the Act. An amendment in 1986 moved the beginning date forward to the first Sunday in April. The European Union adopted standardized dates in 1996; the dates, used by the United Kingdom for many years, are the last Sunday in March to the last Sunday in October.

In 2005, the U.S. Congress enacted the Energy Policy Act, which changed Daylight Saving Time dates again. As of March 2007, Daylight Saving Time begins on the second Sunday in March and ends on the first Sunday of November. States and territories are still able to choose not to observe Daylight Saving Time. The state of Indiana, which was once split in its observation of the time change, adopted a whole-state observation in 2006.

Whether or not “saving daylight” is the most energy efficient method for electricity conservation is still up for debate. But for now, if you live in any of the countries that follow DST, remember to switch your clocks back before you go to sleep Sunday night. Otherwise you’ll wake up thinking you’re late to work.