Daylight saving time (DST) or summer time (see Terminology) is the practice of advancing clocks during the summer months that have more daylight so that people get up earlier in the morning and experience more daylight in the evening. Typically clocks are adjusted forward one hour near the start of spring and are adjusted backward in the autumn.
| Country | Beginning and Ending Dates of DST | |
| AFRICA | ||
| Egypt | Last Friday in April to Last Thursday in Sept | |
| Namibia | First Sunday in September to First Sunday in April | |
| Tunisia | Last Sunday in March to Last Sunday in October | |
| ASIA | ||
| Most states of former USSR | Last Sunday in March to Last Sunday in October | |
| Iraq | First Friday in April to Last Friday in October | |
| Israel | Last Friday before April 2 to Sunday between Rosh Hashana and Yom Kippur | |
| Jordan | Last Thursday of March to Last Friday in September | |
| Lebanon, Kyrgyzstan | Last Sunday in March to Last Sunday in October NOTE: Lebanon did not observe DST from 1900 to 1919, 1924 to 1956, 1962 to 1971 and 1979 to 1983. Kyrgyzstan observed DST only from 1981 to 2005. | |
| Mangolia | Fourth Friday in March to Last Friday in September | |
| Palestinian regions | First Friday on or after 15 April to First Friday on or after 15 October | |
| Syria | March 30 to September 21 | |
| ASTRALASIA | ||
| Australia - South Australia, Victoria, Australian Capital Territory, New South Wales, Lord Howe Island | First Sunday in October to First Sunday in April | |
| Australia - Tasmania | First Sunday in October to Last Sunday in March | |
| Fiji | Stopped in 2000 | |
| New Zealand, Chatham | Last Sunday in September to First Sunday in April | |
| Tonga | First Sunday in November to Last Sunday in January | |
| EUROPE | ||
| European Union, UK | Last Sunday in March at 1 am UTC to Last Sunday in October at 1 am UTC | |
| Russia | Last Sunday in March at 2 am local time to Last Sunday in October at 2 am local time | |
| NORTH AMERICA | ||
| United States, Canada (excluding Saskatchewan and parts of Quebec, B.C., and Ontario), Mexico Bermuda, St. Johns, Bahamas, Turks and Caicos | Till 2006: First Sunday in April to Last Sunday in October. From 2007: Second Sunday in March to First Sunday in November | |
| Cuba | Third Sunday in March to Last Sunday of October | |
| Greenland | Last Sunday in March at 1 am UTC to Last Sunday in October at 1 am UTC | |
| Guatemala, Nicaragua - no longer observe DST | n/a | |
| Honduras | May 7 to August | |
| Mexico (except Sonora) | First Sunday in April to Last Sunday in October | |
| SOUTH AMERICA | ||
| Argentina started from 30 Dec, 2007 ending on 16 March, 2008. In the future, the government will set the dates | Third Sunday in October - to be continued | |
| Brazil (Equatorial Brazil does not observe DST) | Third Sunday in October to Third Sunday in February | |
| Chile | October 11 to March 29 | |
| Falklands | First Sunday on or after 8 September to First Sunday on or after 6 April | |
| Paraguay | Third Sunday in October to Second Sunday in March |
Daylight Saving Time (DST) represents advancing of clocks so that the afternoons have more daylight than the mornings. Typically clocks are adjusted forward one hour near the start of spring and are adjusted backward in autumn. DST is first introduced in 1907 and ever since several countries are following it. In European Union, DST is called Summer Time (ST).
So, if you were born in a country during the months when the DST is observed, your birth time should be adjusted accordingly. Suppose you were born in June at 5.00 pm in USA. Till the end of 2006, USA observed DST from first Sunday in April till last Sunday in October, so your recorded birth time would have been advanced by 1 hr. This 1 hr should be deducted from your recorded time of birth, and hence your actual (standard) time of birth will be 4.00 pm. If you were born during the months when the DST is not observed, then you need not adjust your recorded birth time.