Daylight Saving Time

Daylight saving time (DST) is the practice of advancing clocks during the lighter months so that evenings have more daylight and mornings have less. Typically clocks are adjusted forward one hour near the start of spring and are adjusted backward in autumn.

The modern idea of daylight saving was first proposed in 1895 by George Vernon Hudson and it was first implemented during the First World War. Many countries have used it at various times since then. Much of the United States used DST in the 1950s and 1960s, and DST use expanded following the 1970s energy crisis and has been widely used in North America and Europe since then.

The practice has been both praised and criticized. Adding daylight to evenings benefits retailing, sports, and other activities that exploit sunlight after working hours, but can cause problems for evening entertainment and other occupations tied to the sun. Although an early goal of DST was to reduce evening usage of incandescent lighting (formerly a primary use of electricity), modern heating and cooling usage patterns differ greatly, and research about how DST currently affects energy use is limited or contradictory.

DST clock shifts present other challenges. They complicate timekeeping, and can disrupt meetings, travel, billing, record keeping, medical devices, heavy equipment, and sleep patterns. Software can often adjust computer clocks automatically, but this can be limited and error-prone, particularly when DST dates are changed.

As of now every electronic device programmed as such the time changes according to DST.

Most countries that observe Daylight Saving Time are listed

ContinentCountryBeginning and ending days
AfricaEgyptStart: Last Friday in April
End: Last Thursday in September
NamibiaStart: First Sunday in September
End: First Sunday in April
TunisiaIn 2009 the government of Tunisia canceled DST and kept the standard time all year round.
AsiaMost states of the former USSR.Start: Last Sunday in March
End: Last Sunday in October
BangladeshCancelled in 2010.
IraqStart: First Friday in April
End: Last Friday in October
IsraelStart: Last Friday before April 2
End: The Sunday between
Rosh Hashana and Yom Kippur
JordanStart: Last Thursday of March
End: Last Friday in September
Lebanon, KyrgyzstanStart: Last Sunday in March
End: Last Sunday in October
MongoliaStart: Fourth Friday in March
End: Last Friday in September
Palestinian regions(Estimate)
Start: First Friday on or after 15 April
End: First Friday on or after 15 October
SyriaStart: March 30
End: September 21
AustralasiaAustralia - South Australia, Victoria, 
Australian Capital Territory, New South Wales, 
Lord Howe Island
Start: First Sunday in October
End: First Sunday in April
Australia - TasmaniaStart: First Sunday in October
End: Last Sunday in March
FijiStopped in 2000
New Zealand, Chatham
Start: Last Sunday in September
End: First Sunday in April
TongaStart: First Sunday in November
End: Last Sunday in January
EuropeEuropean Union
Start: Last Sunday in March at 1 am UTC
End: Last Sunday in October at 1 am UTC
RussiaPermanent, as of February 2011
North AmericaUnited States, Canada (excluding Saskatchewan and parts of Quebec, B.C., and Ontario),
Bermuda, St. Johns, Bahamas, Turks and Caicos
Start: Second Sunday in March
End: First Sunday in November
CubaStart: Third Sunday in March
End: Last Sunday of October.
GreenlandSame as EU

HondurasStart: May 7 
End: August
Mexico (except Sonora)Start: First Sunday in April
End: Last Sunday in October

South AmericaArgentina.
Started Sun Dec 30, 2007
Ending 16 March 2008.
Practiced in 2009.
Not currently observed.
Equatorial Brazil does not observe DST.
Start: Third Sunday in October
End: Third Sunday in February
ChileStart:October 11
End: March 29
FalklandsStart: First Sunday on or after 8 September
End: First Sunday on or after 6 April
ParaguayStart: Third Sunday in October
End: Second Sunday in March
UruguayStart: First Sunday in October 
End: Second Sunday in March