What happens when the clocks go back?
When the clocks go back by one hour, the UK is on Greenwich Mean Time (GMT).2 This happens at 2am on the last Sunday in October.
We get less than eight hours of sunlight during the winter solstice, which occurs just before Christmas. Meaning, if we didn’t put the clocks back, sunrise would be after 9am and sunset before 5pm.3
Have you heard of ‘equinox’? It’s an event in which a planet’s subsolar point passes through its Equator. The equinoxes are the only time when both the Northern and Southern Hemisphere experience roughly equal amounts of both daytime and nighttime.4
The dates of when the clocks change line up roughly with the equinoxes, but with a slight bias towards keeping light evenings through September.5