LAST SUNDAY IN OCTOBER
Clocks go back
At 2am the clocks return to 1am. You gain an hour and the UK is back on Greenwich Mean Time.
Before SundayBRITISH SUMMER TIME, EXPLAINED
Fall back.
Gain an hour.
UK clocks go back one hour at 2am on Sunday 25 October 2026.
2AM becomes 1am
+6% Fatal crashes, week after the change
- Spring forward
- Fall back
- GMT in winter
- Since 1916
Twice a year the whole country moves its clocks, and most of us never ask why. Here is where the idea came from, the experiments Britain has tried, and what researchers have found about the switch, in plain English.
Plain English, with the sources linked.
THE SHORT ANSWER
One hour, twice a year.
The UK runs on GMT in winter
and one hour ahead in summer.
LAST SUNDAY IN MARCH
Clocks go forward
At 1am the clocks jump to 2am. You lose an hour and British Summer Time begins.
Where it came from
THE TRADE-OFF
Light moves, not grows
Changing the clocks does not add daylight. It moves an hour of it between morning and evening.
What research saysA QUICK CLOCK CHECK
How far ahead
of Greenwich?
Pick a period to see how far UK clocks ran ahead of Greenwich Mean Time. The figures come from Royal Museums Greenwich.
GMT is the time at the prime meridian in Greenwich. A delegate vote chose Greenwich as the world's prime meridian in 1884.
BEFORE SUNDAY
Four things to do
before the change.
Put the date in the diary
Sunday 25 October 2026, at 2am. The rule is always the last Sunday in October, so next year it is 31 October.
Find the clocks that will not change
Phones and computers usually update themselves. Ovens, cars, wall clocks and heating timers often need changing by hand.
Expect darker evenings
Sunrise and sunset both move an hour earlier on the clock overnight, so the walk home after work gets darker that week.
Remember the spring one
On 28 March 2027 the clocks go forward at 1am and you lose an hour. Spring forward, fall back.
WHAT RESEARCHERS HAVE FOUND
The hour that
costs sleep.
Most concern centres on the spring change,
when everyone loses an hour at once.
+6%
Fatal crashes, week after the change
A University of Colorado Boulder study of 732,835 fatal US road accidents from 1996 to 2017 found a 6% rise during the working week after clocks went forward, about 28 extra deaths a year.
SPRING FORWARD · 2020
Standard time
The position of a sleep medicine body
The American Academy of Sleep Medicine says seasonal clock changes should end in favour of permanent standard time, which it argues fits the body clock best.
SLEEP DOCTORS · 2024
Both findings come from the United States, where the debate is loudest. They describe averages across a population, not what will happen to any one person.
CLOCK HISTORY
Five moments that
set our clocks.
Greenwich wins, 22 to 1
On 13 October 1884, delegates at the International Meridian Conference in Washington voted 22 to 1 to make Greenwich the world's prime meridian.
A builder's pamphlet
In 1907 William Willett published "The Waste of Daylight". His plan moved clocks forward 20 minutes on each of four Sundays in April, 80 minutes in all.
Germany first, Britain weeks later
Germany moved its clocks in April 1916. Britain passed the Summer Time Act on 17 May 1916, a year after Willett died, and changed its clocks that Sunday.
Double summer time
During the Second World War, British Double Summer Time put clocks two hours ahead of GMT in summer and one hour ahead in winter.
Three years without falling back
From 1968 to 1971 the clocks went forward but were not put back. The experiment was discontinued, and the British Summer Time Act 1972 brought back seasonal changes.
QUICK QUESTIONS
The clock change, answered.
Short answers to the questions people ask most.
When do the clocks go back in 2026?
On Sunday 25 October 2026. At 2am British Summer Time the clocks go back one hour to 1am, and the UK returns to Greenwich Mean Time. In 2027 they go back on 31 October.
Do we gain or lose an hour?
In autumn you gain an hour, because 2am becomes 1am again. In spring you lose one: the clocks go forward at 1am on the last Sunday in March, which in 2027 is 28 March.
Why do the clocks change at all?
To move an hour of daylight from summer mornings to summer evenings. The builder William Willett campaigned for it from 1907, and Parliament passed the Summer Time Act in May 1916, a year after he died.
Has the UK ever tried not changing the clocks?
Yes. Between 1968 and 1971 the clocks went forward but were not put back, so the UK stayed an hour ahead of GMT all year. The experiment was discontinued, and in 1972 the British Summer Time Act returned to seasonal changes.
Is Europe getting rid of clock changes?
In March 2019 the European Parliament voted to end seasonal clock changes, originally from 2021, but the plan has stalled and clocks across the EU still change. The UK sets its own rules.
Where the facts come from
Updated
- When do the clocks change? Dates for 2026 and 2027GOV.UK
- What is British Summer Time (BST)?Royal Museums Greenwich
- Why do the clocks change?Royal Meteorological Society
- The 1884 International Meridian Conference and the Greenwich voteLinda Hall Library
- "Spring forward" brings surge in deadly crashes (Current Biology, 2020)University of Colorado Boulder
- Permanent standard time is the optimal choice for health and safety (2024)American Academy of Sleep Medicine