Today approximately 70 countries utilize Daylight Saving Time in at least a portion of the country. The only major industrialized countries not to have introduced daylight saving is China and Japan.
While European nations have been taking advantage of the time change for decades, in 1996 the European Union (EU) standardized an EU-wide "summertime period." The EU version of Daylight Saving Time runs from the last Sunday in March through the last Sunday in October. During the summer, Russia's clocks are two hours ahead of standard time. For example, Moscow standard time (UTC+3) is about a half-hour ahead of local mean time (UTC+2:30); this is about the same situation as Detroit, whose standard time (UTC-5) is also about a half-hour ahead of local mean time (UTC-5:32). During the winter, all 11 of the Russian time zones remain an hour ahead of standard time. With their high latitude, the two hours of Daylight Saving Time really helps to save daylight. In the Southern Hemisphere where summer comes in December, Daylight Saving Time is observed from October to March. (The clock at above left is viewed from within the Musťe d'Orsay in Paris.)
Not the tropics
Equatorial and tropical countries (lower latitudes) generally do not observe Daylight Saving Time since the daylight hours are similar during every season, so there is no advantage to moving clocks forward during the summer. China has had a single time zone since May 1, 1980 observing summer DST from 1986 through 1991; they do not now.
List of countries
Most countries that observe daylight saving time are listed in the table below. They all save one hour in the summer and change their clocks some time between midnight and 3 am.
Beginning and ending days
Start: Last Friday in April End: Last Thursday in September
Start: First Sunday in September End: First Sunday in April
Most states of the former USSR.
Start: Last Sunday in March End: Last Sunday in October
Note that there are many oddities. For example, some parts of the US and Canada do not observe Daylight Saving Time, such as the state of Arizona (US) 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 Japan, Daylight saving was introduced after World War II by the US occupation but was dispensed with in 1952, following opposition from farmers. Despite efforts by the Ministry of International Trade and Industry to have daylight saving introduced to cut Japan's energy consumption, opposition from farmers and the Ministry of Education (who were concerned that lighter evenings would entice school children from their homework) has continued to win the day.
Clark Dam at Butlers Gorge in Tasmania. The bulk of the electricity in Tasmania is generated by hydroelectric stations, causing an energy shortage in the drought of 1967.
In Australia, Daylight Saving was first introduced during World War I under Commonwealth legislation which, due to wartime emergency, was binding on all the States. During the world wars, DST was implemented for the late summers beginning January 1917 and 1942, and the full summers beginning September 1942 and 1943. (Western Australia did not use DST summer 1943).
In 1967, Tasmania experienced a drought, which depleted their reserves of water. The State Government introduced one hour of daylight saving that summer as a means of saving power and hence water. Tasmanians reacted favorably to daylight saving and the Tasmanian Government has declared daylight saving each summer since 1968. After persuasion by the Tasmanian Government, all States (except Western Australia and the Northern Territory) passed legislation in 1971, for a trial season of daylight saving. The following year, New South Wales, South Australia and Victoria joined Tasmania for regular daylight saving, but Queensland did not until 1989.
Tasmania, Queensland and Western Australia have had erratic schedules, often changing their dates due to politics, and to accommodate festivals. For example, in 1992, Tasmania extended daylight saving by an additional month while South Australia began extending daylight saving by two weeks to encompass the Adelaide Festival. In some years Victoria extended daylight saving to the end of March for the Moomba Festival and South Australia and New South Wales followed suit for consistency. Special daylight saving arrangements were observed during the Sydney 2000 Olympic Games.
In response to the problems caused by nonuniformity, a Private Members Bill, the National Measurement (Standard Time) Amendment Bill 1991, was introduced into Federal Parliament in May 1991 by Ron Edwards, Member for Stirling in WA to define a national system of time zones and DST for Australia and its external territories. But in March 1992 the Federal Government decided not proceed with the Bill, and the setting of time zones and daylight saving will remain the responsibility of the State and Territory governments. The lack of uniformity of daylight saving in Australia continues to cause significant problems for transport and communication organizations. It also reduces the number of hours in the working day that are common to all centers in the country. In particular, time differences along the east coast causes major difficulties, especially for the broadcasters of national radio and television that can only be partly overcome by substantial capital investments.
Israel always has Daylight Saving time, but until 2005, it was decided every year by the Ministry of Interior. There was no set rule for Daylight-Saving/Standard time changes, and there was long-running debate between the majority of the secular public who wanted to extend daylight saving as long as possible, and the religious public who wanted to end it before Yom Kippur. One thing was entrenched in law, however: that there had to be at least 150 days of daylight saving time annually. From 1993-1998, the change to daylight saving time was on a Friday morning from midnight IST to 1 a.m IDT; up until 1998, the change back to standard time was on a Saturday night from midnight daylight saving time to 11 p.m. standard time. 1996 is an exception to this rule where the change back to standard time took place on Sunday night instead of Saturday night to avoid conflicts with the Jewish New Year. From 1999-2004, the change to daylight saving time was on a Friday morning, but from 2 a.m. IST to 3 a.m. IDT; and the change back to standard time was on a Friday morning from 2 a.m. IDT to 1 a.m. IST.
The area of Palestine has had varying Daylight Saving Time rules as the dramatic politics of the region have swayed the occupying power. Being closer to the equator than Europe, there is less need for DST, but it has generally been observed anyway. At present, as a sign of independence from Israeli rule, the Palestinian Authority uses a different schedule than Israel.
Early in the twentieth century, the British were quick to standardize time, and from 1917 until 15 May 1948, all of Palestine, including the parts now known as the Gaza Strip and the West Bank, was under British rule, and followed British time changes.
Later, the Gaza Strip was mostly under Egyptian rule from 15 May 1948 until 5 June 1967, and followed Egyptian policy. The rest of Palestine was under Jordanian rule at that time, formally annexed in 1950 as the West Bank (and the word "Trans" was dropped from the country's previous name of "the Hashemite Kingdom of the Trans-Jordan"). So the rules for Jordan for that time apply. Major towns in that area are Nablus (Shchem), El-Halil (Hebron), Ramallah, and East Jerusalem. Both areas followed Israeli time when they were occupied by Israel in June 1967, but not annexed (except for East Jerusalem). The Palestinian Authority was established in 1993, and controlled most towns in the West Bank and Gaza by 1995. The Palestinians began using their own time change dates, separate from Israel's.
In 1999, Jordan decided to implement summer time all year round.
The Antarctic Peninsula (Palmer Station) uses Chile's time zone, the rest of the continent does not. Rothera, a British base, does not implement daylight savings, but instead remains GMT -3. U.S. bases, including both McMurdo and Amundsen-Scott South Pole Station use New Zealand's time zone and daylight saving dates.
See The World Clock for current times and places observing DST at the moment.
Daylight Saving Time (or Summer Time as it is called in many countries) is a way of getting more out of the summer days by advancing the clocks by one hour during the summer. Then, the sun will appear to rise one hour later in the morning when people are usually asleep anyway, at the benefit of one hour longer evenings when awake: The sunset and sunrise are one hour later than during normal time.
DST could save energy (less artificial light is needed during the evening) and make the country more efficient in addition to the pleasing effect of lighter evenings.
To make DST work, the clocks have to be adjusted one hour ahead when DST begins (during spring), and adjusted back one hour to standard time every autumn. There are many countries observing DST, and many who do not.
Note:During the months March/April-September/October, the countries on the northern hemisphere are having their summer and may observe DST, while the countries in the southern hemisphere are having winter. During the rest of the year (September/October-March/April) is the opposite: Winter on the northern hemisphere, summer in the southern... and there might be DST in countries south of equator, but there are many exceptions to this.
Benjamin Franklin suggested the method in 1784, but it was first during World War I, in 1916 in several counties in Europe that DST was adopted, although it was proposed several times before, but rejected.
Daylight Saving Time is difficult to predict in future, many countries change the transition days/principles every year because of special happenings or conditions that has happened or will happen.
DST transitions during 2005
These pages provide time and date for known DST transitions in 2005:
Today it is almost always 1 hour ahead of normal time, but during history there has been several variants of this, such as half adjustment (30 minutes) or double adjustment (2 hours), but adjustments of 20, 40 minutes have also been used. 2 hours adjustment was used in several countries during some years in the 40's and has also been used elsewhere a few times. Half adjustment was sometimes used in New Zealand in the first half of this century. Sometimes DST is used for longer periods than just one summer, as in the United States during World War II. From 3 Feb 1942 to 30 Sep 1945 most of United States had DST all year, it was called "War Time".
How does the transition to DST start?
When clicking on a city in The World Clock you will get information about that city, including when daylight saving start and ends this year, if the city has DST. Let's say that DST starts at local time and DST is one hour:
DST start transition
Local time HR:MI:SE
DST or normal?
DST started, time advanced by one hour
Note that local time is never anything between at the transition from normal to DST, this hour is skipped and therefore this day has only 23 hours (instead of 24 hours). If someone has worked during this night from 0:00 to , they have only worked 7 hours, because of the skipped hour.
How does the transition to DST end?
Let's say that DST ends at local time and DST is one hour ahead of normal time:
DST end transition
Local time HR:MI:SE
DST or normal?
...3596 seconds from to 1:59:57 daylight saving time not shown...
Time is turned back to normal
...3596 seconds from to 1:59:57 normal time not shown...
Note that local time between 1:00:00 and 1:59:59 actually is repeated twice this day, first during DST time, then clocks are turned back one hour to normal time, and the hour is repeated during normal time. To avoid confusion when referring to time within this hour, it is important to tell whether it happened before of after the change back to normal time. The day when DST ends has 25 hours. If someone has worked during this night from 0:00 to 8:00, they have worked 9 hours, because of the repeated hour.
A trip around the world reveals that time isn't a synchronized science
by John Gettings
At on April 3, groggy Americans will turn their clocks ahead one hour, marking the beginning of Daylight Saving Time (DST). But for others around the world (and in Indiana) things aren't that easy.
The federal law that established "daylight time" in this country does not require any area to observe daylight saving time. But if a state chooses to observe DST, it must follow the starting and ending dates set by the law which since 1986 have been the first Sunday in April to the last Sunday in October.
No More Sunlight in Arizona and Hawaii
Arizona and Hawaii and the territories of Puerto Rico, Virgin Islands and American Samoa are the only places in the U.S. that do not observe DST but instead stay on "standard time" all year long. And if you've spent any time in the sweltering summer sun in those regions you can understand why residents don't need another hour of sunlight.
U.S. DAYLIGHT SAVING TIME SCHEDULE
Indiana's Unique Timekeeping
And then there is Indiana. You can get yourself in quite a mess when you ask "What time is it?" in parts of Indiana.
The HoosierState's unique system for observing daylight time is rooted in its once farming-dominated economy. Farmers prefer early daylight to dry their fields and and an early sunset to end their work at a reasonable hour. But some residents think the reason Indiana is missing out on the high-tech boom is that companies are turned off by all the confusion.
The HoosierState's unique system for observing daylight time is rooted in its once farming-dominated economy.
Under the current system, 77 of the state's 92 counties are in the Eastern Time Zone but do not change to daylight time in April. Instead they remain on standard time all year. That is, except for two counties near Cincinnati, Ohio, and Louisville, Ky., which do use daylight time.
But the counties in the northwest corner of the state (near Chicago) and the southwestern tip (near Evansville) are in the Central Time Zone and use both standard and daylight time.
Hoosier Daylight Coalition
So don't let someone tell you that Indiana switches time zones in the summer. It's just that most of the state doesn't move its clocks ahead in April, which allows the Central Time Zone to "catch up" to itómost of it.
The Hoosier Daylight Coalition, a group made up of business leaders, parents, teachers and police, is trying to organize legislation that would simplify things in Indiana. Its hope is that a change will bring new business to the area. But since polls show that half of Indiana residents like things the way they are, it won't be an easy sell.
Comparisons Around the World
About 70 countries around the world observe DST in some form. Here are some interesting facts about some of them:
In Canada, every province except Saskatchewan observes DST. It remains on standard time all year long.
It wasn't until 1996 that our NAFTA neighbors in Mexico adopted DST. Now all three Mexican time zones are on the same schedule as the United States.
Also in 1996, members of the European Union agreed to observe a "summer-time period" from the last Sunday in March to the last Sunday in October.
In the winter months, Russia, which spans over 11 time zones, is always one hour ahead of standard time. In the summer, Russians turn their clocks ahead one more hour.
Most countries near the equator don't deviate from standard time.
In the Southern Hemisphere, where summer arrives in what we in the Northern Hemisphere consider the winter months, DST is observed from late October to late March.
Three large regions in Australia do not participate in DST. Western Australia, the Northern Territory, and Queensland stay on standard time all year. The remaining south-central and southeastern sections of the continent (which is where Sydney and Melbourne are found) make the switch. This results in both vertical and horizontal time zones Down Under during the summer months
China, which spans five time zones, is always eight hours ahead of Greenwich Mean Time and it does not observe DST.
Daylight time begins in the United States on the first Sunday in April and ends on the last Sunday in October. On the first Sunday in April, clocks are set ahead one hour at local standard time, which becomes local daylight time. On the last Sunday in October, clocks are set back one hour at local daylight time, which becomes local standard time.
Not all places in the U.S. observe daylight time. In particular, Arizona, Hawaii, and most of Indiana do not use it.
Many other countries observe some form of "summer time", but they do not necessarily change their clocks on the same dates as the U.S.
Daylight time and time zones in the U.S. are defined in the U.S. Code, Title 15, Chapter 6, Subchapter IX -
History of Daylight Time in the U.S.
Although standard time in time zones was instituted in the U.S. and Canada by the railroads in 1883, it was not established in U.S. law until the Act of March 19, 1918, sometimes called the Standard Time Act. The act also established daylight saving time, a contentious idea then. Daylight saving time was repealed in 1919, but standard time in time zones remained in law. Daylight time became a local matter. It was re-established nationally early in World War II, and was continuously observed from 9 February 1942 to 20 September 1945. After the war its use varied among states and localities. The Uniform Time Act of 1966 provided standardization in the dates of beginning and end of daylight time in the U.S. but allowed for local exemptions from its observance. The act provided that daylight time begin on the last Sunday in April and end on the last Sunday in October, with the changeover to occur at local time.
During the "energy crisis" years, Congress enacted earlier starting dates for daylight time. In 1974, daylight time began on 6 January and in 1975 it began on 23 February. After those two years the starting date reverted back to the last Sunday in April. In 1986, a law was passed permanently shifting the starting date of daylight time to the first Sunday in April, beginning in 1987. The ending date of daylight time has not been subject to such changes, and has remained the last Sunday in October.
Information provided courtesy of U.S. Naval Observatory