# Seasonal time changes in Europe

> Live situation record from CLSTR: https://clstr.news/situations/seasonal-time-changes-in-europe
> Updated: 2026-10-26T09:20:21.000Z. Sources: 16. Developments: 3.

The transition from daylight saving time to winter time is scheduled for the night between Saturday, October 24, and Sunday, October 25, 2026, when clocks will be set back one hour from 3:00 AM to 2:00 AM.

Medical research has highlighted specific physiological risks associated with this shift. Studies in journals such as Internal and Emergency Medicine and Sleep Medicine have noted correlations between seasonal time changes and increased risks of heart attacks, strokes, and traffic accidents. The disruption to circadian rhythms can cause imbalances in melatonin and serotonin levels, potentially leading to fatigue, mood swings, and fluctuations in blood pressure. While the change provides an extra hour of sleep, the most critical period for physiological adaptation is typically between the third and fifth day after the change, though full adjustment may take up to two weeks.

Health experts, including the National Institute of Sleep and Vigilance, note that this shift can cause ‘social jetlag.’ While digital devices often adjust automatically, users are advised to manually check analog clocks, bedside alarms, and household appliances like heating systems. Furthermore, physician Beatrice Mahler notes that disruptions to the central biological clock can impact sleep, hunger, and alertness. Metabolic processes may also be affected; for instance, slower stomach emptying could lead to higher blood glucose and triglyceride levels after meals. These metabolic disturbances are considered reversible as the body resynchronizes, typically within one to three days.

In Serbia, the shift will result in significantly shorter days, with daylight duration decreasing to approximately 10 hours by late October.

## Timeline

### 2026-10-26: Health impacts of the transition to winter time

Physician Beatrice Mahler warns that the shift to winter time can disrupt circadian rhythms, affecting sleep, digestion, mood, and metabolic health for several days.

2 sources. https://clstr.news/cluster/health-impacts-of-the-transition-to-winter-time-1

### 2026-10-17: Winter time transition approaches with health and daylight implications

The upcoming shift to winter time will disrupt circadian rhythms, potentially impacting health through increased risks of sleep disorders and cardiovascular issues as daylight hours decrease.

2 sources. https://clstr.news/cluster/winter-time-transition-approaches-with-health-and-daylight-implications

### 2026-09-25: Winter time transition scheduled for October 25, 2026

The transition to winter time on October 25, 2026, will see clocks set back one hour. While providing extra sleep, the shift in light exposure may cause temporary fatigue and disrupt circadian rhythms.

4 sources. https://clstr.news/cluster/daylight-saving-time-transition-scheduled-for-october-2026-4

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Cite as: Seasonal time changes in Europe. CLSTR, https://clstr.news/situations/seasonal-time-changes-in-europe