A heat dome is a stationary high-pressure system that can remain over a region for several days, trapping hot air and humidity and pushing temperatures to dangerous levels. As air sinks under high pressure, it becomes compressed and warms further. Scientists link this phenomenon to large-scale shifts in the jet stream, whose northward undulations can create persistent high-pressure systems that effectively lock heat in place. In this sense, the heat dome describes the atmospheric mechanism, while the resulting heatwave is what people experience at the surface.

Europe is currently enduring a severe early-summer heatwave affecting countries including France, Italy, Spain, and the United Kingdom. France has been especially hard hit, with about half of the country placed under red heat alerts and multiple heat-related fatalities reported, including drowning incidents connected to attempts to cool off. The situation is further worsened by limited air-conditioning infrastructure in many parts of Europe, with temperatures in some areas expected to reach around 40°C (104°F).

Meteorologists warn that the extreme heat is likely to persist for several days. They also caution that June temperature records may not only be broken but surpassed at unprecedented levels, highlighting the growing intensity and frequency of extreme heat events linked to changing atmospheric patterns.

(AP News, June 24, 2026)