Summer time in Europe
Summer time in Europe is the variation of standard clock time that is applied in most European countries (apart from Iceland, Georgia, Azerbaijan, Belarus, Turkey, and Russia) in the period between spring and autumn, during which clocks are advanced by one hour from the time observed in the rest of the year, in order to make the most efficient use of seasonal daylight. It corresponds to the notion and practice of daylight saving time (DST) to be found in many other parts of the world.
In the EU, EFTA and associated countries, European Summer Time begins at 01:00 UTC/WET (02:00 CET, 03:00 EET) on the last Sunday in March and ends at 01:00 UTC (02:00 WEST, 03:00 CEST, 04:00 EEST) on the last Sunday in October each year; i.e. the change is made at the same absolute time across all time zones. European Union Directive 2000/84/EC makes the observance of summer time mandatory for EU member states (except overseas territories), though a proposal to repeal this directive and require that member states observe their own choice year-round is currently going through the legislative process as of March 2019.
Summer Time lasts, depending upon the calendar year, for either 30 or 31 weeks of the year.
Summer Time was first introduced during the First World War. However, most countries discontinued the practice after the war. It was then restarted in various countries during the Second World War and its immediate aftermath. Again it was widely cancelled by the 1950s, but reintroduced in isolated cases until the late 1960s, when the energy crisis of the late 1960s and early 1970s began to prompt policymakers to reintroduce Summer Time across the continent. It has remained in place in most European countries since then.
Historically the countries of Europe had different practices for observing Summer Time, but this hindered coordination of transport, communications, and movements. Starting in 1981 the European Commission began issuing directives requiring member states to legislate harmonised start and end dates for Summer Time.
Since 1981 each directive has specified a transition time of 01:00 UTC and a start date of the last Sunday in March, but the end dates have differed. Successive Directives laid down two dates for the end: one on the last Sunday in September applied by the continental Member States, and the other on the fourth Sunday in October for the United Kingdom and Ireland. In 1996 the end date was changed to the fourth Sunday in October for all countries. In 1998 the end date was changed to the last Sunday in October; this happened to be the same as the previous rule for 1996 and 1997. The ninth directive, Directive 2000/84/EC, currently (2018) in force, specifies this rule.
There were proposals in 2015 and 2016 from members of the European Parliament to abolish summer time observance, but the European Commission did not at that time put forward proposals to be considered, saying it had not found conclusive evidence in favour of a change, and member states were divided. It did however note that a cost would be incurred if harmonisation between member states' summer time rules was lost. In 2017 the Finnish and Lithuanian parliaments both voted in favour of proposals calling on the EU to reconsider daylight saving, with similar criticism from Poland and Sweden. The European Commission at the time was reviewing the practice.
On 8 February 2018, the European Parliament voted to ask the European Commission to re-evaluate DST in Europe. After a web survey showing high support for not switching clocks twice annually, on 12 September 2018 the European Commission decided to propose that an end be put to seasonal clock changes (repealing Directive 2000/84/EC). In order for this to be valid, the European Union legislative procedure must be followed, mainly that the Council of the European Union and the European Parliament must both approve the proposal.
Under the proposal, member countries were expected to decide by 31 March 2019 which time they would observe year round. This was however considered a fairly tight timescale by many. The Internet Assigned Numbers Authority, which coordinates changes to the time zone database used by most computers and smartphones, notes that "With less than a year's notice there is a good chance that some computer-based clocks will operate incorrectly after the change, due to delays in propagating updates to software and data." The airline industry points out the complexity of revising all airline schedules, particularly in terms of ensuring slot availability on flights outside the EU, and recommends keeping the status quo or deferring the change until at least 2021. An informal meeting of EU transport ministers on 29 October 2018 suggested that many member states would not support the "unrealistic" timetable and that implementation could be pushed back to 2021.
Discussions have shown support for year-round "winter time" in e.g. Denmark, the Netherlands (UTC+01:00), and Finland (UTC+02:00) while permanent summer time was supported in Portugal (UTC+01:00), Poland (UTC+02:00), and Cyprus (UTC+03:00). Spanish opinion is split on the matter; the mainland largely favours shifting to UTC, while the Balearic Islands would prefer to remain on UTC+01:00 and the Canary Islands on UTC-01:00.
On 4 March 2019, the European Parliament Transport and Tourism Committee approved the Commission's proposal by 23 votes to 11. The start date will however be postponed until 2021 at the earliest, to ensure a smooth transition, and the Commission must ensure that countries' decisions to retain winter or summer time are coordinated and do not disrupt the internal market. This decision was confirmed by the full European Parliament on 26 March; it must now be approved by the Council of Ministers. Under the draft directive, member states would be able to choose whether to remain on their current summer time, in which case the last transition would be on the last Sunday of March 2021, or their current winter time, which would take permanent effect from the last Sunday of October 2021.
A consultation by the Irish government found that 80% of those surveyed would not support any measure that resulted in different time zones between Northern Ireland and the Republic. In July 2019, Ireland announced its opposition to the proposed directive and intends to lobby other EU states on the issue. A qualified majority of 55% of member states representing at least 65% of the European population is required for the Council of Ministers to implement a directive. In the UK, the House of Lords launched a new inquiry in July 2019 to consider the implications of the European changes, explore the preparations that should be made and the factors that should inform the UK's response. The United Kingdom is due to leave the EU before the reform becomes effective; any new EU directive would apply during the transition period (if any) but thereafter the UK could choose to make its own arrangements. If the UK were thus to continue observing summer/winter time, Northern Ireland would have a one-hour time difference for half the year either with the rest of Ireland or with the rest of the UK. In September 2018, the UK Government said that it "has no plans" to end daylight saving.
Table of transition dates for European Summer Time
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:
A formula which can be used to calculate the beginning of European Summer Time is:
Sunday (31 − ((((5 × y) ÷ 4) + 4) mod 7)) March at 01:00 UTC
The corresponding formula for the end of European Summer Time is:
Sunday (31 − ((((5 × y) ÷ 4) + 1) mod 7)) October at 01:00 UTC
where y is the year, and a mod b is b times the fractional part of a/b. These formulae are valid until 2099.
Double Summer Time
"Double Summer Time" (two hours ahead of local winter time) has been observed on some occasions, notably in 1921, 1941–45, and 1947. See:
Countries not switching to and from summer time
There are four countries that do not use summer time, but keep the same time all year.
Some may be thought of as using "permanent" summer time, since they use time zones allocated to regions further east than themselves. Belarus explicitly decided to stay permanently on (what it formerly called) summer time after 2011.
Spain, France, Belgium, and the Netherlands may also be thought of as observing "summer time" throughout the winter, and "double-summer time" during summer, because of their positions to the west of the central European time zone.
- Belarus switched to daylight saving time in Spring 2011 and did not switch back to standard time, and is now observing UTC+03:00 all year round. The midpoint of Belarus has longitude 28°E (corresponds to (UTC+1.8).
- Iceland observes UTC+00:00 all year round despite being at longitudes (13°W-24°W) which would indicate UTC-01:00. Iceland's high latitude (the Reykjavík region, home to nearly two-thirds of the country's people, is at 64°N) means that sunset and sunrise times change by many hours over the year, and the effect of changing the clock by one hour would, in comparison, be small.
- Russia used "permanent summer time" from 2011 to 2014. In October 2014 Russia changed permanently back to standard time UTC+03:00 in the country's west, including Moscow), setting the clocks back one hour at the same time as other European countries did.
- Turkey decided to stop daylight saving time in September 2016, but decided to stay on UTC+03:00 throughout the year rather than switching back to its original time zone UTC+02:00.
In most of Europe, the word Summer is added to the name of each European time zone during this period: thus, in the UTC+01:00 time zone, Central European Time becomes Central European Summer Time (UTC+02:00).
During World War II, when the Protectorate of Bohemia and Moravia became a de facto part of Nazi Germany, summer time was used from 1940. In 1940/1941 and 1941/1942, the summer time was kept continuously even during the winter.
Summer time has been observed in Denmark since 1980. A national association against summer time (Landsforeningen mod Sommertid) exists, which celebrated the EU commission preliminary decision in August 2018.
Part of the Kingdom of Denmark, Greenland observes Summer Time simultaneously with Europe. Summer Time thus begins at 00:00 East Greenland Time on Sunday, and 22:00 West Greenland Time on Saturday, and ends at 01:00 EGST on Sunday and 23:00 WGST on Saturday. It was introduced in 1980 when Greenland was legally a part of Denmark without local rule. The most other EU Overseas countries and territories do not observe summer time. Exceptions, based on company decisions, are the northeastern coast around Danmarkshavn (UTC year-round) for Thule Air Base (which follows Atlantic Time and observes in accordance with US and Canadian rules)
In Estonia summer time was not used in 1989–1996 and 2000–2001. It was used under Soviet rule in 1981–1988.
In Finland, summer time has been used on a regular basis since 1981.
A citizens' initiative to abolish daylight saving time was signed by 70,000 Finnish citizens. It was presented to the Finnish parliament in June 2017.
France and Monaco
From 1923 until the Second World War, France and Monaco observed summer time from the last Saturday in March until the first Saturday in October. During the Second World War France also observed summer time. However, after the war the practice was abandoned (since the country changed time zones instituting de facto permanent summer time). In 1976, summer time was reimplemented because of the oil crisis.
Since UTC+00:00 is France's "natural" time zone (extreme points correspond to UTC-0:20 to UTC+0:38), its use of UTC+01:00 in winter could be seen as a form of daylight saving time, while its use of Central European Summer Time (UTC+02:00) in summer can be seen as a form of "double summer time".
Summer time was first introduced during World War I by the German Empire from 1916 to 1918. After the end of the war and the proclamation of the Weimar Republic in November 1918, summer time ceased to be observed. Summer time was reintroduced in 1940, during World War II, to try to save energy for the war economy. After the defeat of Germany, summer time was retained by the occupation powers. In 1945, Berlin and the Soviet Occupation Zone even observed Central European Midsummer Time (Mitteleuropäische Hochsommerzeit, MEHSZ; GMT+03:00): in 1947, all of Germany switched to midsummer time from 11 May to 29 June. After the Federal Republic (West Germany) and the German Democratic Republic (East Germany) were established in 1949, summer time again ceased to be observed in 1950.
In 1978, West Germany decided to reintroduce summer time, following the example set by several neighbouring states in the aftermath of the 1973 oil crisis. However, it only came into effect in 1980, after West and East Germany reached an agreement to observe summer time simultaneously from the last Sunday in March (02:00 CET) to the last Sunday in September (03:00 CEST). Thus both German states observed the same time until the German reunification in 1990, after which the reunified Germany retained the laws and thus also the Time Act (Zeitgesetz) of West Germany.
After 1980, West and East Germany; since 1991 reunified Germany: Central European Summer Time.
Büsingen am Hochrhein, a small exclave of Germany entirely surrounded by Swiss territory, did not implement summer time in 1980 but observed the same time as Switzerland; thus there was a one hour time difference between this village and the rest of Germany. For the tz database, the zone Europe/Busingen was created in its 2013a release, because since the Unix time epoch in 1970, Büsingen am Hochrhein has shared clocks with Zurich, but not with Germany every year.
Germany follows the EU rules regarding the start and end times and dates for summer time.
Summer time was first introduced in Greece in 1932, from July 6 to September 1, but the idea was then quickly abandoned.
In the early 1970s and in the aftermath of the 1973 energy crisis that led many European states to implement summer time in order to save energy, Greece reintroduced summer time in 1975 for the period March–September.
Since 1997 Greece follows the EU rules regarding the start and end times and dates for summer time.
Summer time was first introduced in Hungary in 1916, and it was observed until 1919. After that, summer time was in use between 1941–1949 and 1954–1957. Summer time has been in use again since 1980 and follows EU rules.
In the Republic of Ireland, Irish Standard Time (IST) (UTC+01, Western European Summer Time) is observed during Summer (March to October). IST is sometimes mistaken for "Irish Summer Time", though this is incorrect. Winter Time (UTC+00, WET is observed in the rest of the year.
(Northern Ireland, as part of the United Kingdom of Great Britain and Northern Ireland, observes UK time. As of December 2018, this is the same as the rest of Ireland).
Italy, San Marino, and Vatican City
Summer time is known as "ora legale" (literally "legal hour", referencing the fact that it is mandated by law) in Italy, and it has been adopted and abolished several times: it was observed from 1916 to 1920 and between 1944 and 1948. A law was approved in 1965 that took effect the following year, and made the application of summer time mandatory in the whole country. Since 1996, it has been coordinated with the European Union. San Marino and Vatican City State share land borders solely with Italy and observe the same time as in Italy.
The Netherlands did not use a standardised time until 1909, when Amsterdam Time was introduced. Amsterdam time was 19 minutes and 32 seconds ahead of GMT (Greenwich Meridian time). Later this was corrected to GMT+00:20 for the sake of simplicity.
In 1940 the German occupants forced the Netherlands to observe CEST, Germany's Daylight Saving Time, effectively advancing its timezone by one hour and 40 minutes. This time stayed in effect year round until 1942, when the normal clock followed the German DST switches.
In Norway, summer time was observed in 1916, 1940–45, and 1959-65. The arrangement was controversial, and in 1965 the Norwegian parliament (Stortinget) voted to discontinue the practice. Their neighbour, Sweden, did not use it.
In Poland, "the summer time" was observed in the following years:
- 1916 - 1919
- 1940 - 1949
- 1957 - 1964
- 1977 - (still)
In the years 1979 - 1995 the last day of summer time was the last Sunday of September. In 1996 it was changed to the last Sunday of October, to synchronise with other countries of the EU.
Most of Portugal operates Western European Time and Western European Summer Time.
For many years, the official time in Madeira was one hour later than that in Lisbon, and the Azores were two hours behind. Today in Madeira, the official time is the same as that of Lisbon and, in the Azores, it is one hour behind Lisbon. The start and end dates for summer time in Portugal follow the pattern in the rest of the EU..
Summer time in Romania (locally known by "Ora de Vară") was originally introduced in 1932 (between 22 May and 2 October). Between 1933 and 1940 summer time started on the first Sunday in April and ended on the first Sunday in October. Summer time was abandoned in 1941 and reintroduced in 1979. Until 1996, with few exceptions, summer time in Romania follows European Union rules.
A decree of the Russian Provisional Government introduced summer time (Russian: летнее время) in Russia on 1 July 1917, and clocks moved one hour forward. A decree of the Soviet government led to the abandonment of this system five months later: clocks moved one hour back again on 28 December.
From 1930, Decree time had the effect of imposing year-round time-zone advances in the Soviet Union.
A decision of the Council of Ministers of the USSR reintroduced summer time in the USSR (Moscow Summer Time, for example) on 1 April 1981, and its practice continued into post-Soviet times until 2011. The changeover dates in Russia were the same as for other European countries, but clocks were moved forward or back at 02:00 local time in all zones. Thus in Moscow (local time = UTC+03:00 in winter, UTC+04:00 in summer), summer time commenced at 02:00 UTC on the day before the last Sunday in March, and ended at 03:00 UTC on the day before the last Sunday in October. (Note that "day before the last Sunday" is not the same as "the last Saturday" in a month where the last day is a Saturday.)
On 8 February 2011, Russian President Dmitry Medvedev announced cancellation of biannual clock changes in Russia in favor of a permanent switch to summer time. An hour was added in March 2011 for the last time, and clocks did not move back again. At the same time some of Russia's time zones were consolidated. After this reform many Russian cities had a "standard time" two hours more than would be suggested by their "astronomical time" (because the original standard time was already ahead of astronomical time in many areas).
During his 2012 election campaign, Vladimir Putin proposed re-introducing summer time, as some workers had complained about not seeing any daylight during the winter, since the sun had not risen when they went to work. According to a report in the International Herald Tribune, Russian citizens remembered the winter of 2011-12 as the "darkest winter on record" as a result of the time change. However, Putin later said it would be up to then Prime Minister Medvedev's cabinet to decide how to proceed with a seasonal time shift, and it decided to stay with the 2011 policy.
Slovakia used summer time (locally known as Letný čas) in 1916, 1917, and 1918, as part of the Austro-Hungarian Empire, then in the early 1940s as part of Nazi Germany, and annually from 1979 as part of Czechoslovakia.
After several years, Slovakia established the rule that summer time begins in the last weekend of March (during the night from Saturday to Sunday) and ends in the last weekend of September.
After the dissolution of Czechoslovakia in 1993, Slovakia continued to use summer time. Since 1996 summer time has been prolonged about one month so it lasts until the last weekend in October, in accordance with European Union rules.
Summer time in Slovenia (locally known as "Poletni čas") was introduced on 16 November 1982 when it was one of the Yugoslavia republics. Same law was valid until 1996 when the end of summer time was changed from first Sunday in October to last Sunday in October. In 2006, the European Union standard was adopted and is still used today.
Spain including the Canary Islands has summer time, applying EU rules regarding the start and end times and dates.
In 1918 Spain observed summer time for the first time, and then introduced and abolished several times. It was abolished autumn 1949, and then reintroduced 1974 and has been used since. Spain used GMT+00:00 before 1940 and GMT+01:00 from 1940 as standard time. The Canary Islands used GMT-01:00 before 1946 and GMT+00:00 since 1946 as standard time.
Since UTC+00:00 is Spain's "natural" time zone (extreme points except Canary Islands correspond to UTC-0:37 to UTC+0:17), its use of UTC+01:00 in winter could be seen as a form of daylight saving time, while its use of Central European Summer Time (UTC+02:00) in summer can be seen as a form of "double summer time".
In Sweden summer time was originally introduced on 15 May 1916. It proved unpopular, and on 30 September in the same year, Sweden returned to year-round standard time. This continued for more than half a century.
On 6 April 1980, Sweden again introduced summer time, and since then summer time has been observed every summer in Sweden. Except for the introduction year 1980, summer time has always started on the last Sunday in March. It ended on the last Sunday in September during the years 1980-1995, and has ended on the last Sunday in October since 1996, following a unification of start/end dates of summer time within the EU as well as in several European countries then outside the EU.
The transit authority Västtrafik changes its clocks at 04:00, so that the last tram that leaves around 3:30 actually goes 2:30 on the last weekend of October for those who have changed their clocks at the legal time. The public transport company SL changes their clocks at the legal time, and runs extra departures during the October transition hour.
Switzerland and Liechtenstein
The last country in Europe to adopt summer time, in 1981, was Switzerland, even though summer time had been rejected by 52.1% of voters in a federal referendum in 1978. Since 1996, Swiss summer time has followed EU regulations. It had formerly been in use in 1941 and 1942. Liechtenstein observes the same time as Switzerland. The German village of Büsingen am Hochrhein, a small exclave, entirely surrounded by Swiss territory, also observes the same time as in Switzerland; it did not implement summer time in 1980, and observed the same time as Switzerland, so that there was a one hour time difference between this village and the rest of Germany.
Summer time was introduced in Turkey in 1947, but suspended from 1965 to 1972. Since 1974, Turkey follows European Summer Time.
In 2008, the Turkish Ministry of Energy proposed that Turkey should abolish summer time while at the same time switching to UTC+02:30, originally from 2009 onwards, but when this appeared infeasible, to start in 2011, the plan has not been heard of since.
For the year 2011, Turkey switched to European Summer Time at 3:00 am (03:00) on Monday 28 March, one day later than the rest of Europe, to avoid disrupting the national university entrance examinations held on 27 March.
Once again, for the year 2014, Turkey switched to European Summer Time at 3:00 am (03:00) on Monday 31 March, one day later than the rest of Europe, to avoid disrupting the local elections held on 30 March.
In 2015, Turkey delayed the switch from European Summer Time by 2 weeks, to 4:00 am (04:00) on Sunday 8 November, two weeks later than the rest of Europe, due to the calling of a snap general election on Sunday, 1 November.
In 2016, Turkey scrapped winter time, by switching to New Turkey Time. This means permanent UTC+03:00, which was used during summer time in Turkey. The switch was on 12:00 am (00:00) on Thursday 8 September, in reality stopping switches between summer and winter time.
On 20 September 2011 the Verkhovna Rada (Ukrainian parliament) voted not to return from Eastern European Summer Time to Eastern European Time. This change would have had the effect of moving Ukraine into the Further-eastern European Time zone UTC+03:00 along with Belarus and western Russia (which do not observe summer time). However, on 18 October 2011 the Parliament canceled these plans and the country returned to Eastern European Time as scheduled. 295 MPs voted in favour out of 349 registered MPs.
Crimea and regions of eastern Ukraine under the control of pro-Russian separatists observe Further-eastern European Time.
In the United Kingdom, local time during this period is known as British Summer Time (BST) (UTC+01:00, WEST) while local time during the rest of the year is normally referred to as Greenwich Mean Time (GMT), (UTC+00:00, WET).
Legislation: Summer Time Act 1916; Summer Time Act 1922; Time (Ireland) Act, 1916; Summer Time Act, 1925; Emergency Powers (Defence) Act, 1939; The Summer Time Order 1964; The Summer Time Order 1967; Summer Time Act 1972; The Summer Time Order 1997; The Summer Time Order 2002.
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, at 01:00 UTC (Thus summer time ends at 01:59:59 UTC+01:00).
- Summer Time starts: Last Sunday in March
- Summer Time ends: Last Sunday in October
- The choice should be either summer or winter time of their current time zone, however there is no obligation, so a new time zone could be chosen as well.
- If the current Commission proposal is approved by the Council of Ministers, and member states opt to remain on winter time year round, the March 2021 clock change would be the final clock change.
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