Europe Heatwave Brings Tropical Nights With Overnight Lows Above 20°C

France, Spain, and the UK are experiencing daytime temperatures up to 40°C this week as a heatwave continues across western Europe. France’s national weather service placed more than half of the country’s 96 departments under red alert and stated the heat will not ease before Friday, 26 June.

Authorities in Paris banned alcohol sales at the annual Music Day festival on 21 June and allowed swimming in Canal Saint-Martin starting 23 June. Parks and gardens in the city will stay open around the clock.

Tropical nights defined Tropical nights occur when temperatures remain above 20°C for a full 24-hour period. The UK Met Office reported that the annual probability of three consecutive tropical nights in July has risen from less than 1 percent in pre-industrial conditions to about 20 percent today.

Health effects A data scientist at the World Resources Institute stated that nighttime heat increases cardiovascular stress and sleep disturbance because people often lack access to air-conditioned spaces at home. Studies link sustained high overnight temperatures to higher mortality rates, especially among older adults and those with pre-existing conditions.

Air-conditioning units in Europe have more than doubled since 1990, yet they still cover only about 20 percent of buildings. The same units release refrigerants that trap far more heat than carbon dioxide, adding to outdoor temperatures in dense urban areas.