"Daylight Saving Time (abbreviated DST) is a system in which clocks are set forward in order to have more daylight in the evenings (and less in the morning). This system is used to conserve energy since the use of electrical lights is decreased in the evening.
In DST, clocks are set forward one hour in early spring and they are set back one hour in autumn. One easy way to remember which way to set your clocks is, "Spring forward, fall back."
An idea similar to Daylight Saving Time was first proposed by Benjamin Franklin in 1784, when he urged residents of Paris, France, to get up earlier in the morning in order to save evening candle use (at the time, Franklin was the USA's first ambassador to France); his proposal did not involve changing the setting of clocks. In 1907, William Willet proposed the ideas of changing clocks for DST to the British, but his idea was rejected.
The first countries to adopt DST were Germany and the UK, who began using it in 1916 (during World War I). In 1918, the USA adopted new time zones (to help synchronize railroad schedules) and began using DST. Today, most of North America and Europe (and parts of Australia and South America) use DST.
In the USA, DST begins on the second Sunday in March at 2AM (2AM suddenly becomes 3AM) -- DST ends on the first Sunday in November at 2AM (2AM suddenly becomes 1AM). Also, in the U.S., DST is NOT observed in Hawaii and Arizona."