It’s time to change the clocks forward by an hour tonight as British Summer Time (BST) begins for the 2024 summer months. But why do we have daylight saving time? And when does the time change?
When do the clocks change in March 2024?
In the UK, the clocks will go forward by one hour on Sunday 31 March 2024, when local time hits 1:00am. The new local daylight time will therefore be 2:00am.
The change in clocks means that sunset will be one hour later on 31 March 2024 than the day before, moving from 6:31pm in London to 7:32pm.
The clocks went back by an hour for the winter on 29 October 2023 – bet you wish you’d savoured that extra hour in bed now.
British Summer Time (BST) will last from now until Sunday 27 October 2024 when the UK switches back to Greenwich Mean Time.
Smartphones, tablets, computers and other internet-connected devices will automatically synchronise their time settings, so don’t worry about missing that morning meeting.
On the other hand, wall clocks, some car clocks, watches and devices without internet connectivity will require manual adjustment for time changes – so maybe do worry after all.
Why do the clocks change?
Sadly, there isn’t really a scientific explanation for why we do this dance, but there is at least some logic to it. Essentially, we introduce daylight saving time to allow people to make the most of the day as the nights get longer in the northern hemisphere for summer (the same switch happens in many countries in the southern hemisphere too when their summer rolls around).
So, in a sense, you have daylight saving to thank for the barbeques, long walks and drinks you can enjoy with friends for an extra hour after work in the summer.
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What is the history of daylight saving time?
Many people credit Benjamin Franklin for coming up with the idea of daylight saving time (DST) thanks to a letter of his that was published. In the letter, he noted that Parisians economised on candles by making the most of daylight hours where possible.
But despite Franklin’s keen observations, he didn’t have much to do with DST and its history in different countries around the world is long, winding and convoluted. We won’t bore you with it here.
To keep it brief, most people credit New Zealander George Hudson with the idea of switching back and forth by an hour twice a year in 1895. He was an entomologist, meaning someone who studied insects. Presumably, he needed the extra daylight to catch butterflies or some other bug-related reason.
In the US, daylight saving was first implemented for seven months in 1918 as a wartime measure to conserve energy. Year-round daylight saving was brought in during World War II again, after which states were free to choose whether to observe DST until the Uniform Time Act standardised daylight saving in 1966.
Initially, the law set DST for the period from the last Sunday in April to the last Sunday in October, but it was expanded to the March-November period we’re now familiar with in 2007.
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Why do people want to scrap daylight saving time?
The argument for getting rid of DST does have some scientific grounding. For example, studies have shown that losing an hour of sleep causes an uptick in heart attacks and teen sleep deprivation. Somewhat more serious than missing your 9:00am doctor's appointment, then.
Moreover, gaining an hour of light in the evening means losing light in the morning. Our bodies are designed to be woken up by morning light, and like a shot of coffee in the morning, it helps keep us alert.
Losing that precious morning light could even negatively affect your mood. It is thought that this is partly what causes seasonal affective disorder in winter. The best way to treat it is by using light boxes to simulate natural light in the morning.
Do any countries not use daylight saving time?
For those of us in countries where daylight saving is adopted, it's as familiar as brushing your teeth twice a day. But we’re in the minority.
Only around 70 of the 195 countries in the world mess about with the clocks twice a year as we do; it just doesn’t make much sense if you live near the equator and get the same amount of sunlight all year round.
As a consequence, major economies like Japan, India and China don’t use daylight saving.
Interestingly, some places in the world take it a step further. 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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