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Setting the clocks for daylight savings

Daylight savings: Why do the clocks change?

Published: 26th March, 2022 at 04:00
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We all know the saying ‘spring forward, fall back’, but why – and when – do we change the clocks in the UK? And is it good for us in modern society?

It’s that time of year again when we’re robbed of an hour's worth of sleep. The upside, however, is that we’ll get longer, lighter evenings as we approach summer.

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But when do the clocks change? And what exactly does Coldplay have to do with Daylight Saving Time? Read on for answers to this, and more.

When is Daylight Saving Time in 2022?

In the UK, the clocks go forward one hour at 1am on Sunday 27 March 2022, marking the start of Daylight Saving Time, which is often referred to as simply ‘Daylight Savings’ or ‘summer time’. This means that sunrise will change from around 6am to an hour later at 7am, but will stay light until around 7pm. Then as the days get longer as we head towards the solstice in June, it will stay light for longer in the evening.

Daylight Saving Time ends at 2am Sunday 30 October 2022, when the clocks go back an hour, and we recover our lost hour of sleep.

If you have a smartphone or any other devices connected to the internet, they will update automatically. Most car clocks, battery-operated wall clocks and yes, even the dreaded oven clock, will need to be changed manually.

Is Daylight Saving Time the same as British Summer Time?

Daylight Saving Time is the same as British Summer Time, here in the UK. It's the period during the summer, from the end of March to the end of October when the clocks are one hour forward.

Why do the clocks change?

The main reason we have Daylight Saving Time is simply to make better use of the daylight available. Between March and October, an hour of daylight is borrowed from the morning and added to the end of the day. In modern society, this means saving a fraction on energy bills, which as we all know, are rather high at the moment.

When did Daylight Saving Time start?

We began using Daylight Saving Time only relatively recently, although it was first suggested by Benjamin Franklin back in 1784. He suggested that if we started our days earlier, when it’s lighter, then it would save on candles.

Fast forward to 1907, the great-great-grandfather of Coldplay’s lead singer, Chris Martin, published a leaflet entitled The Waste Of Daylight. As a keen golfer and horse rider, William Willett was eager to make the most of the daylight hours and campaigned for the rest of his life. Although his proposal was not a straightforward one; it involved moving the clocks forward by 80 minutes, in four separate increments of 20 minutes each Sunday at 2am.

In the UK, Daylight Saving Time came into use in 1916, due to the costs of energy usage during the war. However, it was Canada that became the first country to implement Daylight Saving Time, in 1908. The US followed suit in 1918.

What is standard time?

Standard time refers to the local time when Daylight Saving Time is not in use. For us here in the UK, it’s widely known as Greenwich Mean Time (GMT) and sometimes referred to as simply ‘winter time’.

Is changing the clocks twice a year bad for us?

It’s an argument that comes around every year. Some people welcome the change as it heralds a new season, and for some, it’s a mere nuisance.

But for others, it can have significant health impacts.

The transition to and from Daylight Saving Time has been reported to cause jet-lag type symptoms, an increased risk of adverse cardiovascular events, mood disorders and vehicle collisions. Losing just that one hour of sleep results in a 24 per cent increase of heart attacks the next day.

A 2020 study into the effects on sleep from Daylight Saving Time, published in the Journal Of Clinical Sleep Medicine, noted that Daylight Saving Time is less aligned with human circadian biology, resulting in not only acute personal disruptions but also significant public health and safety risks.

You might experience jet-lag-type symptoms on Monday morning after the clocks change © Getty

However, despite this, it’s possible that the US might actually adopt Daylight Saving Time permanently. Recently, the Sunshine Protection Act was passed in the US Senate on 15 March 2022. If it were to pass in the House of Representatives too - and, of course, signed by the president – the US would observe Daylight Saving Time all year-round.

Speaking on the Senate floor, Senator Marco Rubio said, “We see an increase in heart attacks, car accidents, and pedestrian accidents in the week that follows the changes.” He also claims a decrease in crime, decreases in child obesity, and decrease in seasonal depression that many experience during standard time.

But there have been objections to implementing permanent Daylight Saving Time. A 2019 study into the effects of social jetlag in the US, published in the Journal Of Health Economics found that "an extra hour of natural light in the evening reduces sleep duration by an average of 19 minutes and increases the likelihood of reporting insufficient sleep."

The researchers from the same study also found that “the discontinuity in the timing of natural light has significant effects on health outcomes typically associated with circadian rhythms disruptions (e.g., obesity, diabetes, cardiovascular diseases, and breast cancer).”

Another study noted that more research was needed that considers individual chronotypes, sleep characteristics and gender. Permanent Daylight Saving Time would also mean that in some areas of the UK, like the far northwest of Scotland, sunrise would occur as late as 10am in the winter months.

This raises the question – if we stop changing the clocks back and forth, should we stay on standard time, or Daylight Saving Time? The jury’s still out, so for now, at least, it’s worth just getting your head down an hour early on Saturday night, instead of losing a precious hour of sleep.

Which countries do not use Daylight Saving Time?

Only around 70 countries (of 195) worldwide use Daylight Saving Time.

Japan, India and China, as well as most countries near the equator, do not use Daylight Saving Time. There are some places, however, that have their own unique variation. The Antarctic research station Troll, for example, switches between Greenwich Mean Time (GMT) and Central European Summer Time (CEST), which have a difference of two hours.

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Authors

Holly SpannerStaff Writer, BBC Science Focus

Holly is the staff writer at BBC Science Focus. Before joining the team she was a geoenvironmental consultant and holds an MSc in Geoscience from UCL.

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