Darker nights arrive as clocks go back this weekend

Sunset over Hollingworth Lake

It is the official end of British Summer Time (BST) this weekend.

BST ends at 2.00am on Sunday 27 October, so clocks need to go back an hour to 1.00am to revert to Greenwich Mean Time.

In the UK, the clocks go forward one hour at 1am on the last Sunday in March, marking the beginning of Daylight Saving Time, also known as British Summer Time, and back one hour at 2am on the last Sunday in October, returning to Greenwich Mean Time (GMT).

Clocks will go forward again on Sunday 30 March 2025.

Daylight Saving Time was introduced in the UK with the passing of the Summer Time Act on 17 May 1916. The clocks were altered the following Sunday, 21 May 1916, returning to GMT on 1 October 1916.

However, the clocks have also been altered by more than the usual hour forwards and backwards.

Britain adopted British Double Summer Time during World War Two in 1941, which saw clocks being put forward two hours ahead of GMT. The clocks were turned back to GMT at the end of summer 1945, but – due to severe fuel shortages through the previous harsh winter – returned to British Double Summer Time for the summer of 1947.

A three-year experiment between 1968 and 1971 saw Britain trial British Standard Time (GMT +1) all year round, putting the clocks forward as usual by one hour in March 1968, and not putting them back until October 1971.

Europe, and the UK, are far from the only places to alter time.

The majority of the United States – barring Arizona and Hawaii – put their clocks forward on the second Sunday in March and back on the first Sunday in November.

Similarly, some states in Australia choose to observe Daylight Saving Time, albeit in reverse. Western Australia, the Northern Territory and Queensland do not alter their clocks.

For the states that observe the time shift, Daylight Saving Time runs from the first Sunday in October, where the clocks are turned an hour forward, through to the first Sunday in April, when they are changed back.