London uses Greenwich Mean Time (GMT, UTC+0) in winter and British Summer Time (BST, UTC+1) in summer. Clocks go forward at 01:00 GMT on the last Sunday of March and back at 02:00 BST on the last Sunday of October.
Time zone facts
- IANA time zone: Europe/London
- Country: United Kingdom (GB)
- Coordinates: 51.5074°, -0.1278°
Greenwich and the origin of world time
The Prime Meridian runs through the Royal Observatory in Greenwich, east London. For more than a century GMT was the world’s reference time; today that role belongs to Coordinated Universal Time (UTC), which matches GMT in everyday use.
Note that London is not on UTC+0 all year: from late March to late October it is one hour ahead of UTC.
Business hours
Offices typically work 09:00–17:30, Monday to Friday. London’s position makes it a bridge between time zones: its morning overlaps with Asia’s afternoon and its afternoon with the North American morning.
Seasonal daylight
At over 51° north, London’s day length changes dramatically — from under 8 hours around the December solstice to more than 16 and a half hours in late June.