As temperatures soared during the summer of 2026, Europe experienced a series of compounding and interconnected environmental issues, according to a new analysis.

According to data from the Copernicus Climate Change Service (C3S) , Europe’s summer was not just defined by extreme heatwaves, but also by rising sea-surface temperatures, low river flows and exceptionally dry soil.

The report found Western Europe experienced its warmest summer on record, with an average temperature of 21.7 degrees Celsius, surpassing the previous record set in 2003.

And it was not just the temperatures themselves, but the persistence and geographical extent of the heat which was also remarkable.

The researchers found countries in Western Europe experienced an average of 17 days where temperatures went above 30 degrees Celsius, compared with 11 in 2003 and seven in 2025.

And across western Europe, strong heat stress – when heat begins to affect the human body - occurred on a record 41 days by the end of the season, five more than in 2003.

Dr. Samantha Burgess, strategic climate lead at the European Centre for Medium-Range Weather Forecastssaid the most exceptional temperatures occurred in late spring and early summer, during an online press conference.

Dr. Burgess added that the heat was not only remarkable for its intensity, but also for its geographical extent, with nearly a quarter of Europe experiencing its warmest summer on record.

But she said sea-surface temperatures also reached record highs , particularly in the Bay of Biscay, the Western Mediterranean, the Irish Sea, and parts of the North Sea.

“When we look at some of these extremes in the Western Mediterranean, daily sea surface temperatures reached almost 30 degrees Celsius,” she said.

“But heat is only part of the story,” added Dr. Burgess.

“The other part was the compounding impacts we observed over the last few months, and this was very much set up by a dry spring that gave way to increasingly dry periods over the summer.”

She explained a dry spring led to a deficit in rainfall in Central Europe, which resulted in exceptionally dry soils and low river flows, which continued into the summer.

Dr. Burgess said figures from the Standardized Precipitation Evapotranspiration Index, showed drought affected almost half of Europe by the end of August.

She added the 12 major European river systems experienced a water deficit of 69 cubic kilometres, which is the equivalent of two years’ worth of European public water supply.

Dr. Burgess added the persistent dry conditions and repeated heatwaves across Europe during the summer also contributed to an exceptionally active wildfire season.

According to data from the European Forest Fire Information System, by 2 September, the area burned across the European Union was almost twice the 2006-2025 average for that time of year, with particularly extensive activity in Spain and France.

Data from the Copernicus Atmosphere Monitoring Service (CAMS) showed that wildfire emissions in Europe by the end of summer were among the top 10 highest since 2003, exposing millions of people to dangerous levels of air pollution.

“One of the defining characteristics of summer this year was that it was not a single record; it was the way that multiple records appeared together across the climate system,” said Dr. Burgess.

“We have seen dry soils intensifying temperatures, we’ve seen meteorological drought spreading, rivers reaching record lows, and wildfire risk increasing.

“What began as a meteorological story describing the atmosphere and how the atmosphere has influenced our weather has really become a water story, a health story, and an ecosystem story impacting the economics of Europe.”

Last month, a study by the Triodos Bank estimated the extreme summer weather could reduce EU GDP approximately €180 billion and would effectively erase the growth previously forecast for the year.