When and why do the clocks go forward?

This weekend clocks in the UK will 'spring forward' by an hour marking the return of lighter evenings as the UK moves closer to summer.

The clock change happens at 01:00 GMT on 29 March 2026, when we will change to British Summer Time (BST), which is also known as Daylight Saving Time (DST).

For many people the prospect of longer, lighter evenings is a welcome boost - and a key marker that we have left the winter behind us - despite the initial loss of an hour's sleep on the actual night itself.

If you find it hard to remember which way the clocks will change, then the phrase "spring forward, fall back" is a useful reminder.

When the clocks change, sunrise will shift an hour later. In the days immediately after the change people who are up early will notice darker mornings, which can take a little getting used to.

The payoff comes later in the day as evenings become noticeably brighter, with sunset pushed forwards by an hour.

Following the spring equinox most of the northern hemisphere is now enjoying more than 12 hours of daylight each day.

As spring progresses, the gap between sunrise and sunset will keep widening until the summer solstice on 21 June when daylight will be at its peak. In the far north of the UK, particularly northern Scotland, there will be close to 19 hours of daylight, with twilight lingering well into the night and barely any true darkness.

BST will end this year on 25 October when clocks in the UK 'fall back' from 02:00 to 01:00, marking the return to GMT.

If you want precise timings for your location, you can easily check local sunrise and sunset times on the BBC Weather website or through the BBC Weather app.

Daylight Saving Time (DST) — the practice of putting clocks one hour ahead during the summer months — was introduced by Germany in 1916, in the middle of the First World War.

The idea was driven by the need to conserve vital resources, particularly coal. By making better use of natural daylight, countries could reduce reliance on electric lighting and heating in the evenings, while also encouraging longer periods of productivity during daylight hours.

Germany's experiment quickly caught on and within weeks several other nations followed suit, including the UK, which adopted the system under the name British Summer Time.

The approach was taken even further during World War Two, when the UK introduced British Double Summer Time. This was where clocks were moved two hours ahead of GMT during the summer. Even in winter, when clocks were set back, they remained one hour ahead of GMT, again to maximise usable daylight and support wartime productivity.

Although originally a wartime measure, daylight saving became a lasting feature in many countries, continuing to shape daily routines, work patterns, and how people experience daylight throughout the year.

Supporters of BST often argue that lighter summer evenings improve road safety, reducing traffic accidents at busy commuting times. The issue gained national attention between 1968 and 1971, when the UK ran a three-year trial keeping BST all year.

Road casualty figures fell during this period, although later analysis suggested much of the improvement was likely due to drink-driving laws introduced in 1967, rather than the clock change itself.

The trial also exposed clear regional differences. In northern Scotland the impact was less positive. Here on the shortest winter days sunrise did not occur until around 10:00 in some places, resulting in darker mornings and a rise in serious road casualties. These concerns underpin the Scottish government's long-standing opposition to retaining BST during winter.

As a result proposals to end the twice-yearly clock change have repeatedly stalled, and there are currently no plans to alter daylight saving in the UK.

Critics also point to the disruption caused by changing the clocks, often comparing it to mild, nationwide jet lag. Losing an hour of sleep in spring has been linked to short-term effects on mood, concentration, and mental well-being.

One practical frustration has eased, however, with smartphones and connected devices now updating automatically, the seasonal time change is harder to miss —even if the debate around it remains unresolved.