This is when the clocks go forward in 2021 - and why they change

With the hope of brighter days ahead as the Covid vaccination rollout continues, attentions turns to spring and the easing of some restrictions.

Daylight hours are increasing following the winter solstice just before Christmas - meaning the days are getting longer and there will soon be a change to the clocks.

This symbolises the start of British Summer Time.

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Here's when the clocks change, if they go forwards or backwards and why it is done in the first place.

Do clocks go forward or back in spring?

Twice a year people across the UK have to alter their clocks either an hour forward or an hour back, depending on the start or end of the British summer.

The clocks go forward at 1am on the last Sunday of March, meaning an hour less in bed, and go back at 2am on the last Sunday in October every year in the UK.

So that means we lose an hour during the night in spring, effectively a 23-hour day, compared to when we gain an hour in the autumn, when there is a 25-hour day.

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This is to maximise the number of sunlight hours we get during the days over the summer - a time zone referred to as the British Summer Time (BST).

When do the clocks change in 2021?

The clocks go forward at 1am on Sunday 28 March 2021.

Initially we will notice slightly darker mornings and lighter evenings as the number of daylight hours continue to get longer up to the summer solstice.

This will last until 2am on Sunday 31 October 2021 when the clocks go back.

An easy way to remember this is ‘spring forwards, fall back’.

Why do we get more daylight hours in the summer?

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The reason why we get more daylight hours in the summer and shorter days in the winter is because the earth's axis is tilted at 23.4 degrees.

This means the hemisphere closest to the sun gets more direct light from the sun's rays, as the earth completes a full orbit of the sun in a year.

It is why the northern hemisphere has longer days in the summer months and the southern hemisphere has longer days in the months of November to March.

Why do we change the clocks twice a year?

British Summer Time has been established in the UK for more than a century.

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A campaign led by builder William Willett resulted in the Summer Time Act of 1916 being introduced in the UK.

Willett, a keen golfer who wanted more daylight hours on the greens, wrote about his proposal in a pamphlet called The Waste of Daylight.

It was also thought to benefit more than just golfers, as it would help conserve energy through reduced need for light and heat resources.

Willett's idea was introduced a year after his death, as the UK followed in the footsteps of Germany and Austria.

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