The scorching weather that has smashed temperature records across Europe this week shows the growing number and intensity of heat waves on the continent.
Europe is the continent that has experienced the fastest warming since 1990, according to data from the U.S. National Oceanic and Atmospheric Administration (NOAA).
As cities from Rome to London swelter in the unusually early spell of intense temperatures, here are five things to know about heat waves in 21st-century Europe.
The intense heat wave that hit Western Europe during the first half of August 2003 was a real shock in several countries.
The exceptional temperatures endured in France, Italy, Spain and Portugal led to tens of thousands of deaths: a European study published in 2007 estimated there were 70,000 "additional deaths" in 16 countries during the summer of 2003.
In the following years, a number of countries set up alert systems for intense summer heat, such as France's "heat wave plan."
Another heat wave that hit Russia in 2010 led to nearly 56,000 "additional deaths," according to the Russian statistics agency.
And more than 61,000 deaths are thought to be attributable to the heat during the summer of 2022 in 35 European countries, according to a French-Spanish study.
While the 2003 heat wave mainly affected Western and Southern Europe, every region of the continent has been hit by heat waves since the start of the century.
Russia's 2010 heat wave, lasting an exceptional 45 days, saw a record temperature of 37.2 degrees Celsius (98.96 degrees Fahrenheit) in Moscow in July.
In June and July 2019, it was mostly northern and western Europe that suffered, with records broken in the Netherlands, Belgium, Germany, and the United Kingdom.
The French record of 46 degrees Celsius, in Verargues in the country's south, dates from that year.
In 2021, it was southern Europe's turn to fry, with an all-time record temperature for Europe of 48.8 degrees recorded in Syracuse in Sicily on Aug. 11, as well as a national record in Spain, and "the worst heat wave since 1987" in Greece, according to Athens.
Heat waves in Europe are covering a bigger geographic area and extending both earlier and later in the calendar than before.
In 2019, and again in 2022, the first heat wave to strike Europe arrived in mid-June, with heat records for the month broken in Germany and Austria in 2022.
The following year, the European heatwave stretched into September, worsening drought conditions in southern Europe.
And this month, an "unprecedented" episode of early heat hit Western Europe: May temperature records fell in France, the U.K. and Portugal, while in Italy several major cities were put on red alert for heat on Thursday.
Studies and scientific bodies agree that heat waves in Europe are becoming more frequent.
French weather service Meteo-France says that of the 51 heat waves recorded nationwide since 1947, 34 have come since 2000 and 26 since 2011.
A German-Romanian study covering the period 1921-2021, published in 2025, concluded that there had been a significant increase in the frequency of heat waves across most regions of Europe, especially over the last 30 years.
Twenty-first-century heat waves in Europe have come with record temperatures, such as the absolute continental peak reached in Syracuse in 2021 – a record confirmed by the World Meteorological Organization (WMO).
Other national records – meaning the highest temperature ever recorded in the country at a single location, not an average – have been set in several European countries in recent years.
These include the French record hit in June 2019, a British record of 40.3 degrees Celsius in July 2022, a German peak of 41.2 degrees in July 2019 and a top Spanish temperature of 47.6 degrees in August 2021.
