Daylight saving time

seasonal adjustment of clocks
(Redirected from Daylight Saving Time)

Daylight saving time (DST) or summer time (ST) is a time to keep during summer. During the summer months, the sun stays 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.

A map showing countries that use daylight saving according to each hemisphere as of April 2023.
  DST in the northern hemisphere summer
  DST in the southern hemisphere summer
  DST no longer used
  DST never used
Diagram of a clock showing a transition from 02:00 to 03:00
Clocks are advanced by one hour during the very early morning at the beginning of DST.
Diagram of a clock showing a transition from 03:00 to 02:00
When DST ends, clocks are set back (as if to repeat one hour) during the very early morning. Specific times vary.

DST helps stores that sell to people after they get off work, and it does not hurt 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:

Iceland, Russia, Belarus, and some parts of Ukraine are countries in Europe without DST.

As of January 2024, the following places plan to start and end DST at the following times:[1][2]

Places DST start DST end Shift
Second Sunday in March at 02:00 First Sunday in November at 02:00 1 hour
Second Sunday in March at 00:00 First Sunday in November at 01:00 1 hour
Last Sunday in March at 01:00 [UTC] Last Sunday in October at 01:00 [UTC] 1 hour
Last Sunday in March at 02:00 Last Sunday in October at 03:00 1 hour
Last Sunday in March at 00:00 Last Sunday in October at 00:00 1 hour
Friday before last Sunday in March at 02:00 Last Sunday in October at 02:00 1 hour
Second Saturday after Ramadan at 02:00 Saturday before last Sunday in October at 02:00 1 hour
Last Friday in April at 00:00 Last Thursday in October at 24:00 1 hour
First Saturday in September at 24:00 [UTC−04:00] First Saturday in April at 24:00 [UTC−03:00] 1 hour
First Sunday in October at 00:00 Fourth Sunday in March at 00:00 1 hour
First Sunday in October at 02:00 First Sunday in April at 03:00 1 hour
First Sunday in October at 02:00 First Sunday in April at 02:00 30 minutes
Last Sunday in September at 02:00 [UTC+12:00] First Sunday in April at 02:00 [UTC+12:00] 1 hour

In the table above, the DST times show the time before being moved forward or back. The shift is how much time is added at the DST start time and subtracted at the DST end time. For example, in Canada and the United States, the local time changes from 02:00 to 03:00 when DST starts and from 02:00 to 01:00 when DST ends. If a time zone is listed (e.g., UTC−04:00), all time zones in a country move forward and backward simultaneously; otherwise, time zones change in their local time. Areas shown in the same color start and end DST within less than a week of each other.

Europe

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European Union

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Since 1971 all clocks in the European Union have changed on same dates and at the same time, 06:00 GMT.[3]

European Summer Time begins (clocks go forward) at 01:00 UTC on the last Sunday in March, and ends (clocks go back) at 01:00 UTC on the last Sunday in October:

Start End
28 March 2021 31 October 2021
27 March 2022 30 October 2022
26 March 2023 29 October 2023
31 March 2024 27 October 2024
30 March 2025 26 October 2025[note 1]
29 March 2026 ? 25 October 2026
28 March 2027 ? 31 October 2027
  1. If the 2018 Commission proposal had been approved by the Council of Ministers, and member states opted to remain on winter time year round, the October 2022 clock change would have been the final clock change.

United Kingdom

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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 GMT+1 in the winter, and DST summer time (GMT+2) in the summer. 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.RoSPA suggests this would reduce the number of accidents over this period as a result of the lighter evenings.[4][5][6]

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.[7]

Middle East and North Africa

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Israel

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Lebanon

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Palestine

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North America

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United States

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The following table lists future starting and ending dates of daylight saving time in the United States:

Year Start End
2021 March 14 November 7
2022 March 13 November 6
2023 March 12 November 5
2024 March 10 November 3
2025 March 9 November 2
2026 March 8 November 1
2027 March 14 November 7

Canada

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South America

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Paraguay

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Oceania

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Australia

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New Zealand

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Automatic adjustment

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Most mobile phones and computers connected to the Internet will automatically adjust their clocks for DST. Some 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.

  1. Member states of the European Union (EU):

    Austria
    Belgium
    Bulgaria
    Croatia
    Cyprus
    Czech Republic
    Denmark[b]
    Estonia
    Finland[c]

    France[d]
    Germany
    Greece
    Hungary
    Ireland
    Italy
    Latvia
    Lithuania
    Luxembourg

    Malta
    Netherlands[e]
    Poland
    Portugal[f]
    Romania
    Slovakia
    Slovenia
    Spain[g]
    Sweden

  2. The Faroe Islands and Greenland are not part of the EU and are listed separately.
  3. Including Åland.
  4. Some parts of Overseas France are part of the EU but do not observe DST.
  5. Only the European part of the Netherlands is part of the EU and observes DST.
  6. Including Azores and Madeira.
  7. Including the Canary Islands, Ceuta, Melilla and plazas de soberanía.

References

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  1. "The World Clock (extended version)". timeanddate.com. Retrieved 1 March 2023.. Detailed DST information about each location, current and historical, can be found under the relevant section of this website, and can be referred to for information in this article unless otherwise specified.
  2. "Time zone database and code". Paul Eggert.
  3. British Summer Time Archived September 2, 2016, at the Wayback Machine
  4. "Press Release October 22, 2008 It's Time for a Change to Save Lives and Reduce Injuries". RoSPA Press Office. Archived from the original on Mar 17, 2009. Retrieved Sep 22, 2016.
  5. "British Summer Time (BST)". NMM – National Maritime Museum. Archived from the original on 2009-08-02. Retrieved 2016-09-22.
  6. Jha, Alok (Mar 29, 2010). "Lighter Later Guardian Article". The Guardian. London.
  7. "Should we change the clocks?". National Farmers Union. Mar 18, 2010. Archived from the original on Mar 30, 2010. Retrieved Sep 23, 2015.

Other websites

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