When do the clocks go forward in 2023? UK's British Summer Time, explained

Find out the exact time the clocks go forward, how it could impact your health, and the bizarre connection between BST and Coldplay's Chris Martin.

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Published: March 25, 2023 at 3:40 pm

Brace yourself: this weekend the clocks go forward, meaning everyone in the UK will stand to lose an hour’s sleep. However, it’s not all bad news, with the start of British Summer Time (BST) meaning longer evenings – in London, the Sun will set at 7:23pm on Sunday.

But when exactly do the clocks go forward? Why do we have British Summer Time in the first place? And how could the shift impact your health? The answers to these questions, and much more, are just below.

When do the clocks go forward?

The clocks go forward by one hour at 1am, Sunday 26 March in the UK. This marks the beginning of British Summer Time.

The change means that in the UK, sunset will occur an hour later, shifting from 6:23pm to 7:23pm (London times). The Sun will also rise an hour later, moving from 5:50am to 6:50am (London times again).

Solar noon, the point when the Sun is at its highest in the sky will shift one hour later from approximately 12pm to 1pm.

The days will continually lengthen until we reach the summer solstice, on 21 June 2023. The clocks will then change backwards by an hour at 2am on Sunday 29 October 2023.

Most of your devices that are connected to the internet, such as your phone or laptop, should update automatically. However, most car clocks, battery-powered wall clocks and your oven clock will need changing manually (hope you remembered where you left the manual).

In the US, the clocks moved forward slightly earlier, at 2am on Sunday 12 March.

Why do the clocks change?

In short, it’s to make better use of natural daylight. During British Summer Time, we’re essentially moving an hour of sunshine from the early morning to the evening, which reduces energy consumption at night – and, of course, allows you more time to enjoy the outside after work.

However, the benefits of changing clocks have been long-debated (more on that below).

When was the first British Summer Time?

Clock changing was only made official in the UK during 1916 in a bid to curb energy usage during the First World War. The US followed suit in 1918.

However, the change was suggested by US polymath Benjamin Franklin and an ancestor of Chris Martin – yes, thatChris Martin from Coldplay.

It was in 1784 that Franklin first proposed changing the clocks according to daylight, arguing people would save on candles.

However, it was only in 1907 that the idea started to gain traction in the UK due to Chris Martin's great-great-grandfather, William Willett. A builder, Willett published a leaflet calledThe Waste Of Daylight that recommended changing the clocks.

But his suggested changes weren’t the ones we have today: Willett argued we should be changing the clocks forward by 80 minutes, in four separate increments of 20 minutes each Sunday at 2am. Now there's a man who's never had to change an oven clock.

Is the shift in time bad for your health?

There’s no clear answer to this – and the question has been debated for decades.

Many cite the change as welcoming a new season, but several studies have found that the transition to British Summer Time may have a detrimental impact on your health.

For instance, one study in theBritish Medical Journalfound that the loss of one hour’s sleepincreases the number of heart attacks throughout the UK by 24 per cent the next day.

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An annualspike in stroke incidents has also been identified in Finlandthe day after their clocks change in March. Additionally, a US study found that their March clock changecosts the country $275 million (£225m) each yearin the loss of productivity due to sleep deprivation.

Interestingly, the UK experimented in an all-year British Summer Time between 1968 and 1971. Thanks to lighter evenings, the number of road casualties significantly fell during this time. However, this clock change was reversed following complaints from northern parts of the UK, areas where mornings were particularly dark.

Which countries do not change their clocks?

Most countries in the world do not change their clocks ever. In fact, only 70 of the 195 UN countries shift their times.

Japan, India and China, as well as most countries near the equator, do not have their own version of British Summer Time or Daylight Saving Time.

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