Western Europe’s average surface air temperature reached 20.74°C in June 2026, exceeding the 1991–2020 norm by 3.05°C and breaking the previous regional record set in June 2025, according to the EU’s Copernicus Climate Change Service (C3S). Globally, the month was the second-warmest June in the ERA5 dataset, at 16.54°C, or 1.39°C above the pre-industrial average. Sea surface temperatures for extrapolar oceans hit a June record of 20.86°C, just 0.01°C above the 2024 high, reflecting both long-term warming and the developing El Niño in the tropical Pacific.

The heat was concentrated in the second half of the month, when a high-pressure “heat dome” settled over western and central Europe, trapping hot air and suppressing cloud formation. The World Weather Attribution network later concluded that such an event would have been virtually impossible without human-induced climate change, and that a comparable heatwave in June 2003 would have been about 2°C cooler. Europe is warming roughly twice as fast as the global average, a trend that scientists at the European Centre for Medium-Range Weather Forecasts (ECMWF) link to changes in atmospheric circulation and Arctic amplification. While El Niño contributed to record ocean warmth, it did not play a significant role in the European heatwave itself, according to a rapid attribution study.

National health authorities reported more than 4,700 excess deaths across France, Belgium, Spain and the Netherlands during the heatwave, with France alone recording over 2,700 excess deaths for the month. Spain’s Carlos III Health Institute attributed more than 1,000 deaths to the extreme temperatures. The World Health Organization has calculated that over 200,000 people have died from anomalous heat in Europe over the past four years. Beyond the human toll, the combination of extreme heat and dry soils—exacerbated by a May heatwave—fuelled wildfires in the Iberian Peninsula and southern France, heightened drought risks in eastern Europe, and reduced river flows. Marine heatwaves in the western Mediterranean and along Europe’s Atlantic coasts added stress to marine ecosystems.

Arctic sea ice extent was about 5% below the June average, the sixth-lowest on record, with the largest deficits in the northern Barents Sea. Antarctic sea ice was roughly 8% below average, also ranking sixth-lowest. The next factual milestone is the evolution of the El Niño event, which ECMWF forecasts will strengthen rapidly in the coming months, likely pushing global surface temperatures higher. A new heatwave was already affecting parts of southern Europe in early July, and Copernicus will publish its next monthly climate bulletin in early August.