What is the name of the summer time zone used in the United Kingdom?

The summer time zone used in the United Kingdom is called British Summer Time, or BST. During BST, clocks are advanced one hour from Greenwich Mean Time, changing the UK’s offset from UTC+00:00 to UTC+01:00.

BST is the United Kingdom’s form of daylight saving time. It normally begins at 1:00 a.m. GMT on the last Sunday in March and ends at 2:00 a.m. BST on the last Sunday in October. The shift gives Britain later sunsets during the warmer months, although it also produces darker mornings.

A common mix-up is treating Greenwich Mean Time as the summer zone. GMT is the UK’s standard winter time; BST is the seasonal summer designation. Western European Time is another name for the UTC+00:00 standard-time zone in parts of Europe, while Central European Time is normally UTC+01:00 and belongs to countries farther east.

The UK first introduced summer time in 1916, following campaigns by builder William Willett. During parts of the Second World War, Britain even used British Double Summer Time, two hours ahead of GMT.