Daylight saving time (DST), often referred to as daylight ‘savings’ time, is a widely used system of adjusting the official local time forward, usually one hour from its official standard time for the duration of the spring and summer months. This is intended to provide a better match between the hours of daylight and the active hours of work and school. The “saved” daylight is spent on evening activities which get more daylight, rather than being “wasted” while people sleep past dawn.
DST is most commonly used in temperate regions, due to the considerable variation in the amount of daylight versus darkness across the seasons in those regions.
Governments often tout it as an energy conservation measure, on the grounds that it allows more effective use of natural sunlight resource in summer time. (People go to bed and wake up earlier, which reduces use of electric lights.) Some opponents reject this argument.
Europeans commonly refer to the system as summer time: Irish Summer Time, British Summer Time, and European Summer Time. This is reflected in the time zones names as well, e.g. Central European Time (CET) becomes Central European Summer Time (CEST).
It is sometimes asserted that DST was first proposed by Benjamin Franklin in a letter to the editors of the Journal of Paris. However, the article was humorous; Franklin was not proposing DST, but rather that people should get up and go to bed earlier.
It was first seriously proposed by William Willett in the “Waste of Daylight”, published in 1907, but he was unable to get the British government to adopt it despite considerable lobbying.
The idea of daylight saving time was first put into practice by the German government during the First World War between April 30 and October 1, 1916. Shortly afterward, the United Kingdom followed suit, first adopting DST between May 21 and October 1, 1916. Then on March 19, 1918, the U.S. Congress established several time zones (which were already in use by railroads and most cities since 1883) and made daylight saving time official (which went into effect on March 31) for the remainder of World War I. It was observed for seven months in 1918 and 1919. The law, however, proved so unpopular (mostly because people rose and went to bed earlier than in current times) that the law was later repealed.
DST commonly begins in the northern hemisphere on either the first Sunday in April or the last Sunday in March, and ends on the last Sunday in October. However, beginning in 2007, the United States will begin observing DST on the second Sunday of March until the first Sunday in November, but if no energy savings can be shown from the extension after the U.S. Department of Energy completes a study of impact of the change, Congress may revert back to the schedule set in 1986 under Section 110 of the Energy Policy Act of 2005. Since 2002, the European Union has fixed the last Sunday in March and the last Sunday in October as start and end dates (European Summer Time).
In the southern hemisphere, the beginning and ending dates are switched; therefore, the time difference between the United Kingdom and Chile may be three, four, or five hours, depending on the time of year.
For me, it just means that everything under the sun will be messed up for the next few weeks.