June Likely Among Europe’s Hottest on Record as Widespread Heatwave Breaks Temperature Extremes

Throughout June, many countries experienced conditions more typical of July and August, with extreme heat stretching from the Arctic region to southern Europe. Meteorological stations reported multiple historic highs, highlighting the growing intensity of heat events across the continent.

In Portugal, the national meteorological service recorded 46.6°C in Mora on 29 June, marking the highest June temperature ever registered in mainland Portugal. In northern Europe, Norway’s Banak station reached 32.5°C, setting a new record for the European Arctic during the month.

The extreme temperatures have triggered widespread health alerts, school closures, and restrictions on outdoor work in several countries as authorities attempt to reduce exposure risks.

The European Centre for Medium-Range Weather Forecasts (ECMWF) estimates that June 2025 will likely rank among the five warmest Junes ever recorded in Europe.

Scientists attribute the prolonged heat to a “heat dome” effect, where a high-pressure system remains stationary over a region for days or weeks, trapping hot air and preventing cooler weather from moving in. This creates increasingly intense and sustained periods of high temperatures.

A strong high-pressure system first developed over Western Europe, affecting Spain and Portugal before expanding into France, Germany, and Italy. Forecasters expect partial relief in some regions as Atlantic weather systems bring thunderstorms and cooler air, although southern countries may continue experiencing extreme heat into the weekend.

France has been among the hardest hit countries. Temperatures in Paris reached 40°C, prompting red-level heat alerts in multiple regions. More than 1,300 schools were closed either fully or partially, and access to the Eiffel Tower summit was temporarily suspended due to unsafe conditions.

French authorities reported that June 2025 became the second hottest June in the country since records began in 1900, surpassed only by June 2003. Meteorologists also confirmed that 30 June was the hottest day ever recorded since measurements began in 1947.

Health impacts have also been significant, with hundreds of people requiring emergency treatment and at least two deaths linked to heat-related illness.

Spain experienced similarly extreme conditions. The national meteorological agency Aemet described June as “extremely hot,” noting that it broke long-standing records and exceeded typical July and August averages.

Spain recorded an average temperature of 23.6°C for June, the highest in 64 years, surpassing the previous record set in 2017. Several individual days also set new temperature records, a pattern scientists say would be highly unusual without climate change influences.

Experts in Spain have linked the severity of the heatwave to global warming, noting that rising sea surface temperatures in the Mediterranean are also reducing the natural cooling effect that coastal regions typically benefit from.

Climate researchers warn that millions of Europeans are currently experiencing dangerous levels of heat stress. Data from the ECMWF shows that many regions have faced unusually high temperatures since early June, with conditions more typical of peak summer occurring much earlier in the year.

The agency also notes that similar extreme heat patterns were observed in 2024, which was already recorded as the hottest year on record globally.

In the United Kingdom, temperatures reached 34.7°C in London, marking the hottest day of the year so far. Preliminary data indicates that the country experienced its second-warmest June since 1884, continuing a broader trend of rising temperatures across all seasons.

The UK had already experienced its warmest and sunniest spring on record, and June continued the pattern with multiple heatwaves and prolonged periods of above-average temperatures.

Climate scientists from the UK Met Office emphasize that human-induced climate change has significantly increased both the frequency and intensity of extreme heat events. They also warn that such conditions are expected to become more common in the future, particularly in southern and southeastern parts of the country.

Overall, experts agree that the current heatwave reflects a broader shift in Europe’s climate, where extreme heat events are becoming more widespread, more intense, and more disruptive to daily life.