Western European Summer Time

Western European Summer Time (WEST, UTC+01:00) is a summer daylight saving time scheme, 1 hour ahead of Greenwich Mean Time and Coordinated Universal Time. It is used in:

The following countries also use the same time zone for their daylight savings time but use a different title:

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+00:00. During the winter, Western European Time (WET, GMT+0 or UTC±00:00) 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 Irish Standard Time during the summer months and changes to UTC±00:00 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.


The following countries and territories use UTC+01:00 during the summer, between 1:00 UTC on the last Sunday of March and 1:00 UTC on the last Sunday of October.

  • Canary Islands, regularly since 1980 (rest of Spain is CEST, i.e. UTC+02:00)
  • 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 Western European Midsummer Time|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


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 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 KingdomEdit

Starting in 1916, the dates for the beginning and end of BST each year were mandated by the Parliament of the United Kingdom. From 1940 to 1945, the country used British Summer Time in the winter months and British Double Summer Time, a further hour ahead of GMT, in the summer months. From 1968 to 1971, the country used BST throughout the year. 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.


  1. ^ a b "STANDARD TIME ACT, 1968".
  3. ^ "timeanddate.com webpage erroneously referring to IST as "Irish Summer Time"". Retrieved 27 August 2009.
  4. ^ "Example of Trinity College, Dublin using the term "Irish Summer Time"". Trinity College, Dublin. Retrieved 27 August 2009.
  5. ^ "Hora Legal em Portugal Continental [Standard and Summer Time in Continental Portugal]" (PDF) (in Portuguese). Astronomical Observatory of Lisbon. Retrieved 20 May 2014.
  6. ^ "Time Changes in Lisbon over the years (1925–1949); Time Zone in Lisbon, Portugal". timeanddate.com. Retrieved 20 May 2014.
  7. ^ Law, Gwillim (30 May 2001). "Time Zones of Portugal". Statoids. Retrieved 20 May 2014.
  8. ^ "Decreto Regional n.º 5/82/M, de 3 de Abril [Regional Decree 5/82/M, 3 April 1982]" (PDF). Diário da República, I Série, n.º 78, 7 de Abril de 1982 (in Portuguese). 7 April 1982. pp. 777–778. Retrieved 20 May 2014.
  9. ^ "Standard Time Act, 1968". Irish Statute Book. Attorney General. 15 July 1968.
  10. ^ "Standard time". Focal. Retrieved 17 August 2012.
  11. ^ "Standard Time (Amendment) Act, 1971". Irish Statute Book. Attorney General. 20 July 1971.
  12. ^ "Lighter Evenings (Experiment) Bill [HL]".
  13. ^ "Statutory Instrument 2002 No. 262—The Summer Time Order 2002".

Further readingEdit

  • 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 linksEdit