When do the clocks go forward?

Clocks go forward, 2026 to 2035

Why 1am, and why Sunday

The Summer Time Order 2002 sets the start of summer time at 1am GMT on the last Sunday in March. Choosing a Sunday in the early hours keeps the disruption to a minimum: few people work, few trains run, and most of the country is asleep. Because the moment is fixed in GMT, it is 1am in London and 2am in Paris at the same instant, and the hour's difference with the continent never changes.

The Summer Time Act 1972 defines summer time as one hour ahead of GMT. Before that, the dates were set each year, and during the Second World War the country even ran on double summer time, two hours ahead, in the summer months.

Getting through the short night

Losing an hour affects some people more than others. Children, shift workers and anyone with a fixed medication schedule may want to move bedtime earlier by 15 minutes a night in the days before. Phones change by themselves; ovens, cars and central heating timers do not. Anyone working a night shift works an hour less on the night of the change. Flights and trains run to the new time from 2am, and online timetables already show BST. If you have an important appointment on the Sunday morning, check the time twice.

Lighter evenings

The change moves an hour of daylight from the morning to the evening. By the end of April the sun sets after 8pm in London and much later in Scotland, where sunset in Edinburgh is after 8.30pm. The simulator under the summary shows what your alarm will feel like the morning after. The British Summer Time page explains the history and the debates about keeping summer time all year, and the clocks go back page counts down to October.

Around the world

The whole European Union changes at the same instant as the UK, so the time difference with France, Spain or Germany stays at one hour. The United States and Canada start their summer time earlier, on the second Sunday in March, so for two or three weeks the gap between London and New York is four hours instead of five. Countries close to the equator, and most of Asia and Africa, do not change their clocks at all. In the southern hemisphere, summer time ends around the time it starts in the north, so the gap with Sydney or Auckland changes twice in a few weeks.

If you have regular calls or flights across time zones in late March, the safest approach is to set them in UTC, which never changes, and let each calendar convert to local time. The converter on the British Summer Time page gives the UK time for any UTC time and date.