Which hour happens twice?
The change happens early on Sunday morning, during the night of Saturday 24 October into Sunday 25 October. The UK returns from BST to GMT.
The hour from 1am to 2am occurs twice: first in BST, then in GMT. For example, 1.30am BST and 1.30am GMT are an hour apart. If you have a booking during that hour, ask which one is intended.
Check devices before changing them
For other phones, computers and timers, use the instructions for your device. Automatic time settings can be restricted; check the displayed time before changing it manually.
| What you use | What to check |
|---|---|
| Clock or heating timer without automatic updates | Move it back one hour at the change, following its instructions. |
| iPhone or iPad | Settings > General > Date & Time > Set Automatically. Follow Apple's help if the option is unavailable or the time is wrong. |
| A booking between 1am and 2am on Sunday | Ask whether it means BST or GMT. That hour happens twice. |
| A call with someone abroad | Compare the calendar entry with the original invitation and confirm the time zone if they differ. |
Check the time zone on appointments
Compare important calendar entries with the original booking confirmation, especially overnight bookings and calls involving people abroad. Check the date, displayed time and time zone. If they disagree, ask the organiser to confirm the intended time.
Google Calendar displays events in each viewer's local time zone. On a computer, open the event, choose Edit, then check Time zone beside the event time. Compare the original invitation before changing a booking.
Official information
- GOV.UK: when do the clocks change?
The 2026 date, reversal at 2am and return to GMT. Checked 4 October 2026.
- nidirect: clock-change reminder (2025)
The BST-to-GMT transition and checking non-automatic clocks and timers. Its 2025 date is not the date used in this guide. Checked 4 October 2026.
- Apple Support: date and time settings
iPhone and iPad automatic time settings, troubleshooting and restrictions. Checked 4 October 2026.
- Google Calendar Help: different time zones
Local-time display and computer event time-zone controls. Checked 4 October 2026.