Western European Summer Time

At both the start and end of the schemes, clock changes take place at 01:00 UTC+00:00.

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.

Ireland observes Irish Standard Time during the summer months and changes to UTC+00:00 in winter.

[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] Starting in 1916, the dates for the beginning and end of BST each year were mandated by the Parliament of the United Kingdom.