During the summer months, the sun stays is visible for a longer time, and sunset happens late in the day. For this reason, certain countries advance the time by one hour near the start of summer, and put it back one hour during autumn. The time during summer is called Daylight saving time (DST). In Europe it is called summer time. The time during the winter months is called "standard time".
DST helps stores that sell to people after they get off work, but it hurts farmers and others whose hours are set by the sun. It cuts traffic accident rates. Sometimes it can reduce energy costs, but it can also increase them.
Most of the world's countries do not use DST, but it is common in Europe and North America.
The United States, Australia, the United Kingdom, Canada and many other countries have DST. These countries also have regions that do not have DST:
- United States: most of Arizona and Hawaii
- Australia: Queensland, Western Australia and the Northern Territory
- Canada: Saskatchewan except for a few locations with the border with Alberta and Manitoba
Iceland, Russia, some parts of Ukraine and Belarus are countries in Europe without DST.
USA dates and UK dates
Since 1996 all clocks in the European Union, of which the UK is a member state, have changed on same dates and at the same time, 01:00 GMT.
- British Summer Time starts: Last Sunday in March
- British Summer Time ends: Last Sunday in October
- British Summer Time clocks change at 01:00 (1.00 am) Greenwich Mean Time (GMT).
- USA 2013 date: March 10
- USA 2012 date: March 11
- USA 2011 date: March 13
- USA 2010 date: March 14
- USA 2009 date: March 8
- USA 2008 date: March 2
Permanent GMT+1
Permanent Summer Time has support in some northerly countries such as the UK. It was tried in the British Standard Time experiment, with Britain remaining on GMT+1 throughout the year. This took place between 27 October 1968 and 31 October 1971.
There are proposals for GST+1 in the winter, and double summer time (GST+2) in the winter. In favour are most city dwellers: children do not have to come home after school in the dark, and late afternoon and early evening activities benefit. In favour also were those concerned with accidents, because both accidents and fuel consumption go down.
Against are many farmers in northerly latitudes, because sunrise would occur in winter at about 10.00 in the morning. However, in March 2010 the National Farmers Union said that it was not against Single/Double Summer Time, and is in fact relatively neutral, with many farmers expressing a preference for the change.
Automatic adjustment
Most computers, mobile phones and other devices connected to the Internet will automatically adjust their clocks for DST. Some older computers will not adjust or will adjust the time incorrectly or on the wrong date. Also, computers with more than one operating system may be incorrectly adjusted twice or more when each operating system boots.
Images for kids
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George Hudson invented modern DST, proposing it first in 1895
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In early 2008 central Brazil was one, two, or three hours ahead of eastern U.S., depending on the date.
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Retailers generally favor DST. United Cigar Stores hailed a 1918 DST bill.
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William Willett independently proposed DST in 1907 and advocated it tirelessly.
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Justification for Daylight Saving Time to the effect that it is a more natural adjustment for people rising with the sun.
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The William Willett Memorial Sundial is always on DST.
