Western European Summer Time

Time in Europe:

light blue	Western European Time / Greenwich Mean Time (UTC)
blue	Western European Time / Greenwich Mean Time (UTC) Western European Summer Time (UTC+1)
red	Central European Time (UTC+1) Central European Summer Time (UTC+2)
yellow	Eastern European Time / Kaliningrad Time (UTC+2)
golden	Eastern European Time (UTC+2) Eastern European Summer Time (UTC+3)
light green	Further-eastern European Time (UTC+3)

Light colours indicate where standard time is observed all year; dark colours indicate where a summer time is observed.

Time in Africa

	UTC−01:00	Cape Verde Time
	UTC±00:00	Greenwich Mean Time
	UTC±00:00 UTC+01:00	Western European Time Western European Summer Time
	UTC+01:00	West Africa Time / Central European Time
	UTC+01:00 UTC+02:00	West Africa Time West Africa Summer Time
	UTC+02:00	Central Africa Time / South African Standard Time / Eastern European Time
	UTC+03:00	East Africa Time
	UTC+04:00	Mauritius Time / Seychelles Time

Light colors indicate where standard time is observed all year; dark colors indicate where daylight savings is observed.

Note: The islands of Cape Verde are to the west of the African mainland.

Western European Summer Time (WEST) is a summer daylight saving time scheme, 1 hour ahead of Coordinated Universal Time. It is used in:

• the Canary Islands
• Portugal (including Madeira but not the Azores)
• Ireland
• the United Kingdom
• the British Crown dependencies
• the Faroe Islands
• Morocco in North Africa

Western European Summer Time is known in the countries concerned as:

• British Summer Time (BST) in the United Kingdom.
• Irish Standard Time (IST)^[1] (Am Caighdeánach na hÉireann (ACÉ)^[2]) in Ireland. Also sometimes erroneously referred to as "Irish Summer Time" (Am Samhraidh na hÉireann).^[3][4]

The scheme runs from the last Sunday in March to the last Sunday in October each year. At both the start and end of the schemes, clock changes take place at 01:00 UTC. During the winter, Greenwich Mean Time (UTC+0) is used.

The start and end dates of the scheme are asymmetrical in terms of daylight hours: the vernal time of year with a similar amount of daylight to late October is mid-February, well before the start of summer time. The asymmetry reflects temperature more than the length of daylight.

Ireland observes Standard Time during the summer months and changes to UTC+0 in winter.^[1] As Ireland's winter time period begins on the last Sunday in October and finishes on the last Sunday in March, the result is the same as if it observed summer time.

Usage

The following countries and territories use Western European Summer Time during the summer, between 1:00 UTC on the last Sunday of March and 1:00 UTC on the last Sunday of October.

• Spain
  • Canary Islands, regularly since 1980 (rest of Spain is CEST, i.e. UTC+2)
• Kingdom of Denmark
  • Faroe Islands, regularly since 1981
• Ireland
  • 1916–1939 summers IST
  • 1940–1946 all year IST
  • 1947–1968 summers IST
  • 1968–1971 all year IST
  • 1972– summers IST
• Portugal
  • Continental Portugal^[5]
    • 1916–1921 summers WEST
    • 1924 summer WEST
    • 1926–1929 summers WEST
    • 1931–1932 summers WEST
    • 1934–1941 summers WEST
    • 1942–1945 summers WEST (1942–1945 midsummers WEMT^[6][7]=WEST+1)
    • 1946–1966 summers WEST
    • 1966–1976 all year WEST/CET
    • 1977–1992 summers WEST
    • 1992–1996 winters WEST/CET (1993–1995 summers CEST)
    • 1996– summers WEST
  • Madeira, regularly since 1982^[8]
• The United Kingdom
  • 1916–1939 summers BST
  • 1940–1945 all year BST (1941–1945 summers BDST=BST+1)
  • 1946 summer BST
  • 1947 summer BST (1947 midsummer BDST=BST+1)
  • 1948–1968 summers BST
  • 1968–1971 all year BST
  • 1972– summers BST

Ireland

In Ireland, since the Standard Time (Amendment) Act, 1971, Ireland has used UTC+1 in summer (officially "standard time",^[9] Irish: am caighdeánach,^[10] though usually called "summer time") and UTC+0 in winter (officially "winter time").^[11]

Portugal

Portugal moved to Central European Time and Central European Summer Time in 1992, but reverted to Western European Time in 1996 after concluding that energy savings were small, it had a disturbing effect on children's sleeping habits as it would not get dark until 22:00 or 22:30 in summer evenings, during winter mornings the sun was still rising at 9:00, with repercussions on standards of learning and school performance, and insurance companies reported a rise in the number of accidents.^[12]

United Kingdom

Starting in 1916, the dates for the beginning and end of BST each year were mandated by the Parliament of the United Kingdom. In February 2002, the Summer Time Order 2002^[13] changed the dates and times to match European rules for moving to and from daylight saving time.

Start and end dates of British Summer Time and Irish Standard Time

Note: Until 1 October 1916 time in all of Ireland was based on Dublin Mean Time, GMT − 25 minutes.

References

Further reading

• Prerau, David. Saving the Daylight: Why We Put the Clocks Forward (ISBN 1-86207-796-7) — The Story of Summer Time/Daylight Saving Time with a focus on the UK

External links

• A Brief History of BST/DST
• History of legal time in Britain
• BBC News report: Safety call as clocks go back.
• BBC News report: Tundra time call in clocks debate.
• UK Government Report: Overview of the pros and cons of British Summer Time.
• RoSPA Press Release: RoSPA calls for switch to lighter nights to save lives
• BST FAQ
• Official British Government site listing Summer time dates for 2006–2011 inclusive (Updated March 2008)
• Dates when BST began and ended
• UNIX 'zoneinfo' file for Europe: as well as including a full set of dates for all European countries, it includes many comments on the history of DST in those countries.