GMT in winter, British Summer Time in summer
London uses Greenwich Mean Time (UTC) during standard time and British Summer Time (UTC+1) during daylight saving. A schedule written as 12:00 GMT means a fixed UTC time; it is not the same as noon in London throughout the year.
The UK changes clocks on the last Sundays of March and October. The US uses different dates, which temporarily changes the London–New York difference. Mumbai does not change its clocks, so its difference from London also varies between the two UK seasons.
Upcoming clock changes in London
- Clocks move back 60 minutes: 02:00 → 01:00.UTC+1 → UTC · 01:00 UTC
- Clocks move forward 60 minutes: 01:00 → 02:00.UTC → UTC+1 · 01:00 UTC
Moving forward skips local times; moving back repeats them. For a time within the repeated hour, TimeTravel lets you select the earlier or later occurrence.
Calculated on Oct 18, 2026 from available IANA rules. Governments can revise future rules; refresh this page for an updated calculation.
When it is 09:00 in London
These two dated examples show how the same morning appointment can translate across the year. Each cell includes the destination date, in 24-hour time.
| Destination | January 15, 2026 | July 15, 2026 |
|---|---|---|
| New York | 04:00Jan 15, 2026 | 04:00Jul 15, 2026 |
| Mumbai | 14:30Jan 15, 2026 | 13:30Jul 15, 2026 |
Convert your own date from London. The examples are individual instants, not a fixed year-round difference or a recommendation of working hours.
Reference: GOV.UK: when the clocks change. Guide reviewed September 28, 2026. Method and accuracy.