There are 108 clock changes across 11 dates in the next twelve months. Each one makes a day 23 or 25 hours long somewhere.
The next clock change is on 25 October 2026, affecting 33 time zones.
| Date | Zones | Direction | Day length |
|---|---|---|---|
| 25 October 2026 | 33 | back | 25 hours |
| 30 October 2026 | 1 | back | 25 hours |
| 1 November 2026 | 14 | back | 25 hours |
| 14 March 2027 | 14 | forward | 23 hours |
| 26 March 2027 | 1 | forward | 23 hours |
| 28 March 2027 | 32 | forward | 23 hours |
| 4 April 2027 | 6 | back | 25 hours |
| 30 April 2027 | 1 | forward | 23 hours |
| 5 September 2027 | 1 | forward | 23 hours |
| 26 September 2027 | 1 | forward | 23 hours |
| 3 October 2027 | 4 | forward | 23 hours |
On the day a region moves onto summer time its civil day is 23 hours long. On the day it moves off, the day is 25 hours long and one hour occurs twice. Meridian draws the day that actually exists rather than assuming a fixed grid, which is why the board shows 23, 24, or 25 columns depending on the date.
See local time by city for the transition dates that apply to a specific place.