Should Europe keep summer time all year? The health evidence behind the DST debate

Clocks across the European Union went back by one hour in the night of 24–25 October 2026, returning most countries to winter (standard) time, according to Interia Biznes. The switch reopened a question the EU has been unable to settle for years: should the bloc stop changing clocks altogether, and if so, should it keep summer time or winter time year-round?

What Europeans actually want

A representative survey of 1,111 adult Poles conducted by Europion Polska in October 2026 found that 60% want permanent summer time, 16% want permanent winter time, and 12% want to keep switching twice a year, with 13% undecided, according to aboutmarketing.pl. Preference for summer time rises with age: 49% among 16–29-year-olds versus 69% among people over 60. Half of respondents, 51%, said early darkness after the switch to winter time actually changes their daily schedule.

Poland is not alone in favouring permanent summer time. According to timeanddate.eu.com, France, Denmark, Finland, the Baltic states and Portugal also lean toward permanent summer time, while Greece, Romania, Bulgaria and Cyprus favour permanent winter time. Germany, Italy, Spain, the Netherlands, Belgium, Luxembourg, Austria, Ireland and Czechia have not settled on a position.

Why the EU still hasn't decided

The European Parliament voted in 2019 to end seasonal clock changes, following a 2018 public consultation in which, according to Interia Biznes, around 80% of roughly 4.6 million respondents across the EU favoured abolishing the switch. The underlying European Commission proposal would have let each member state choose its own permanent time, according to Interia Biznes. But under EU rules a time-harmonisation directive needs unanimous backing in the Council, and timeanddate.eu.com reports that "the Council has sat there ever since" with no agreement, largely because northern and southern countries want opposite outcomes. As of October 2026, clocks are set to keep changing in 2026 and 2027 with no fixed timeline for abolition, per the same source.

What the health research shows

While public opinion leans toward permanent summer time, recent scientific modelling points the other way. A study by Stanford Medicine researchers Lara Weed and Jamie Zeitzer, published in the Proceedings of the National Academy of Sciences and summarised by Medical Xpress, modelled how light exposure under different time policies affects circadian rhythm across the United States. The team concluded that permanent standard time (closer to winter time) would be the most beneficial option, projected to lower national obesity prevalence by about 0.78%, or roughly 2.6 million fewer cases, and to prevent around 300,000 stroke cases a year compared with the current switching system.

Permanent daylight saving (summer) time was found to deliver only about two-thirds of that benefit: an estimated 0.51% drop in obesity prevalence (about 1.7 million people) and roughly 220,000 fewer stroke cases annually. The researchers found the current twice-a-year switching produced the worst outcomes of the three options, according to Medical Xpress.

The mechanism, according to the study, is that morning light speeds up the body's internal circadian clock while evening light slows it down; most people need more morning light and less evening light exposure to stay aligned with a 24-hour day. Permanent summer time pushes sunrise later in winter, reducing morning light exposure, which the researchers link to circadian misalignment. The authors noted their model assumed ideal light-exposure habits and did not fully account for weather, geography or time spent indoors.

A gap between preference and evidence

The divide is notable: most survey respondents in Poland say they prefer more evening daylight, which permanent summer time provides, while the circadian-science argument favours standard time because it preserves earlier morning light in winter. Public complaints about winter-time darkness in the Europion Polska survey centred on early evening darkness after work (cited by 51% of respondents), not on morning light availability, which the Stanford-led study identifies as the more significant health factor.

Because the EU Council has not reached the required unanimous agreement, no member state has formally notified the European Commission of a preferred permanent arrangement, according to timeanddate.eu.com. Until that changes, the biannual clock change — and the recurring public debate over it — is set to continue in Poland and across the EU.