Heat domes trap scorching air, driving record temperatures across Europe

A heat dome—a persistent high-pressure system caused by a jet-stream bulge—has settled over western Europe, trapping extreme heat and humidity. As the air descends, it compresses and warms, driving surface temperatures up to 104 °F (40 °C) in countries such as France, Italy, Spain and the United Kingdom. Researchers say the dome’s formation is a key driver of the current heat wave, with climate change making such events more common, intense and longer-lasting.

France has placed roughly half its territory under a red heat-wave alert and recorded around 40 fatalities linked to drowning as people sought relief. Public gatherings, including trains, concerts and sports matches, have been called off, and officials are limiting alcohol consumption outdoors. Health officials stress the importance of hydration, shade, and nighttime cooling to prevent heat-related illness.