The idea of daylight saving was first conceived by Benjamin Franklin in 1784. The “Daylight Saving Time” (DST), called “Summer Time” in some countries, is a way to make better use of daylight: the clocks of a whole nation are moved one hour ahead during the summer months, delaying the use of artificial light in a moment where the working activities are still in full operation. Several studies found that it reduces net traffic accidents and fatalities as well.
Naturally this is not valid for all the places in the world: near the equator, day and night are nearly the same length (12 hours), thus DST is usually not helpful in the tropics, and countries near the equator generally do not change their clocks. But elsewhere on Earth, there is much more daylight in the Summer than in the Winter. The closer you live to the North or South pole, the longer the period of daylight in the summers. In the Southern Hemisphere where summer comes in December, DST is observed from October to March.
Today approximately 70 countries utilize DST in at least a portion of the country. The only major industrialized country not to have introduced daylight saving is Japan. China has had a single time zone since May 1, 1980 observing summer DST from 1986 through 1991; they do not now.
### Countries which use DST | ### Countries which do not use DST
Since 1996 in all the countries of the European Union all time zones change at the same moment: Summer Time begins and ends at 2 am. It starts the last Sunday in March, and ends the last Sunday in October. In Italy DST has been introduced for the first time during the first world war, in 1916. It has been suspended from 1921 to 1940, and from 1942 to 1966 when it has been adopted permanently. Just to have an idea of the huge amount of saving, in 2004 the use of the DST saved in Italy about 60 million of Euros.
In the USA each time zone switches at a different time,but for most of the states DST begins at 2 am on the first Sunday of April. Time reverts to standard time at 2 am on the last Sunday of October.
Note that there are many oddities. For example, some parts of the USA and Canada do not observe Daylight Saving Time, such as the state of Arizona (USA) and the province Saskatchewan (Canada). Observance can also be erratic. For example, Chile delayed its changeover date for the Pope’s visit in 1987, and a presidential inauguration in 1990.
In Australia the setting of time zones and daylight saving remains the responsibility of the State and Territory governments. Tasmania, Queensland and Western Australia have had erratic schedules, often changing their dates due to politics, and to accommodate festivals. The lack of uniformity of daylight saving in Australia continues to cause significant problems for transport and communication organizations. Special daylight saving arrangements were observed during the Sydney 2000 Olympic Games.
