The clocks will go back one hour on Sunday 26th October, marking the end of summer. But why do the clocks change and when did Daylight Savings Time first start?

Why do the clocks change?

Daylight Savings Time (DST) makes the most of increased daylight hours in the Northern Hemisphere. In the UK, we set the clocks ahead an hour in spring, and back an hour in autumn.

According to the Royal Museums Greenwich (RMG), a campaign at the beginning of the 20th century successfully argued in favour of changing the clocks during the summer months to avoid wasting time in the morning.

The Summer Time Act was passed in 1916 and was used in Germany during the Second World War. It began as a way to conserve energy and use fewer resources during the war, also helping to boost productivity. Other European countries soon followed suit, including the UK where it was named British Summer Time (BST).

Other reasons why the clocks change include farmers being able to get their work done, fewer road traffic accidents, people being able to exercise more outdoors, and having longer evenings to support leisure and tourism.

Why do the clocks change back in October?

Marking the end of British Summer Time, the clocks go back in October, giving us an extra hour in bed. Following summer solstice in June, the days gradually become shorter and it gets darker in the morning. Turning the clocks back an hour during autumn gives people more sunlight in the morning.

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Why do the clocks go back at the weekend?

The weekend was chosen for the clocks to change because it is the least disruptive option for schools and businesses.

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Do other countries change the clocks?

Around 70 countries change their clocks. Within Europe, only Armenia, Azerbaijan, Belarus, Georgia, Iceland, Russia and Turkey do not practice daylight saving time.

Will our clocks update automatically?

Digital clocks connected to the Internet, including our phones, should automatically update. Manual watches and clocks need to be wound back.

Curator of the Royal Observatory Louise Devoy explains what happens in Greenwich when the clocks change.

"I have very little work to do when the clocks change! We deliberately keep most of our historic clocks on GMT all year round as they were mainly used before the first daylight saving came into effect in 1916. Visitors arriving at the Observatory in the summer are often confused by the apparent delay shown on the Shepherd Gate Clock but as Britain's first public clock to show GMT, we're proud to continue this tradition," she says.

"The most significant change is our Dolphin sundial which needs to be adjusted four times a year: at the solstices (June and December) and when the clocks change (March and October)."

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Lisa Joyner
Deputy Daily Editor, Country Living and House Beautiful

 Lisa Joyner is the Deputy Daily Editor at House Beautiful UK and Country Living UK, where she's busy writing about home and interiors, gardening, dog breeds, pets, health and wellbeing, countryside news, small space inspiration, and the hottest properties on the market. Previously, she has written for Conde Nast Traveller, House & Garden and Marie Claire magazine. Lisa studied at University For The Creative Arts, where she completed a BA in Fashion Journalism.