The Danish answer to your query is: you set the clock back one hour on the last Sunday in October at 03:00, which effectively moves from summer time (Sommertid) to standard time (Normaltid/Vintertid). In 2025, that means turning the clock back from 03:00 to 02:00 overnight between Saturday and Sunday, specifically on the night of October 25–26, 2025. Details to keep in mind:

• Sommertid (DST) starts: last Sunday in March at 02:00, clocks go forward to 03:00, effectively losing one hour of sleep.
• Vintertid/Normaltid (standard time) starts: last Sunday in October at 03:00, clocks go back to 02:00, effectively gaining one hour.
• This biannual adjustment happens in Denmark and most European countries, though some regions do not observe DST today.

If you’d like, I can confirm the exact date and time for the current year or provide a quick reminder checklist for each year’s DST transitions.