British Summer Time: Seven Months of UTC+1
The UK runs on two offsets. From the last Sunday in March to the last Sunday in October, clocks move forward one hour to British Summer Time (BST, UTC+1). The rest of the year, the country operates on Greenwich Mean Time (GMT, UTC+0).
In July, with London on BST, New York is five hours behind. In January, with London on GMT, New York is still five hours behind. Both countries shift their clocks on similar dates, so the gap to the US East Coast holds steady. The gap to places that do not observe daylight saving, like Japan or Iceland, widens or narrows by one hour between seasons.
When the Clocks Change
The rule is fixed. The dates move.
- BST begins: the last Sunday of March at 01:00 UTC. Clocks go forward one hour, from 01:00 GMT to 02:00 BST.
- BST ends: the last Sunday of October at 01:00 UTC. Clocks go back one hour, from 02:00 BST to 01:00 GMT.
Confirmed dates from the IANA time zone database:
| Event | Date (London local) |
|---|---|
| BST begins 2026 | Sunday 29 March |
| BST ends 2026 | Sunday 25 October |
| BST begins 2027 | Sunday 28 March |
| BST ends 2027 | Sunday 31 October |
The 01:00 UTC trigger is deliberate. Pubs have closed. Most commuter trains have not yet started. The Summer Time Act 1972 defines the BST period. The current alignment (last Sunday of March to the last Sunday of October) was set by the Summer Time Order 2002, matching the European Union schedule. The UK kept that schedule after leaving the EU.
Why Shift the Clocks at All?
The logic is straightforward: move an hour of daylight from early morning, when most people sleep, to the evening, when they are awake. On the June solstice in London (21 June 2026), sunrise is at 04:42 and sunset at 21:21. That is 16 hours and 39 minutes of daylight.
The Summer Time Act 1916 introduced the modern system during World War I to save fuel. William Willett had campaigned for the idea since 1907, but Parliament acted only when coal shortages made the argument urgent.
Will the UK Abolish DST?
No change has happened. As of October 2026, the rules stand.
The UK government said in 2019 it has no plans to alter daylight saving. Time is a reserved matter for Westminster. The Scottish Parliament, the Senedd and the Northern Ireland Assembly cannot set a different zone.
The European Parliament voted in 2019 to end seasonal clock changes by 2021. Implementation stalled in the Council of the EU. No decision was enacted. The UK, having left the EU on 31 January 2020, is not bound by any future EU move on DST.
In October 2024 the British Sleep Society published a position statement recommending abolition of DST and a permanent switch to GMT. Their argument: shifting clocks damages circadian health, and standard time aligns social schedules with solar time better.
No bill has been introduced. No parliamentary debate leading to a vote has taken place.
Campaign groups disagree on the remedy. "Lighter Later" wants permanent BST for longer evenings. Safety groups in Scotland oppose it, citing dark winter mornings. Neither side has shifted government policy.
Daily Life Under BST
Two things change for most people: when the sun appears, and the arithmetic for international calls.
Daylight. On the shortest day (21 December 2026), London gets 7 hours 50 minutes of daylight, with sunrise at 08:03 and sunset at 15:53. On the longest (21 June 2026), it gets 16 hours 39 minutes. BST pushes that light into the evening. Summer sun lingers past 21:00.
Time differences. When London moves to BST, offsets to cities in zones without DST shift. On 15 January (GMT), Dubai is 4 hours ahead and Singapore is 8 hours ahead. On 15 July (BST), Dubai is 3 hours ahead and Singapore is 7 hours ahead. São Paulo goes from 3 hours behind in January to 4 hours behind in July. A recurring meeting with someone in a non-DST country needs a manual calendar adjustment twice a year. A digital calendar set to "Europe/London" handles this automatically, provided the organiser's zone is correct.
Transport and broadcasting. National Rail timetable changes land in May and December, not on clock-change weekends. On the night the clocks go back, trains running at 01:00 GMT are held or adjusted. BBC Radio 4 broadcasts the Greenwich Time Signal every hour, in GMT during winter and BST in summer.