Italy and Western Europe swelter under extreme heatwave, red alerts in 12 cities rising to 16

A severe heatwave is tightening its grip on Italy and much of Western Europe, prompting health authorities to issue the highest level of alert for a growing number of urban centres. The Italian Ministry of Health's heat bulletin placed 12 cities under a red alert on Monday, with that figure climbing to 15 on Tuesday and 16 on Wednesday. The heat, fed by a massive bubble of subtropical air, is expected to last at least until the end of the month.

Red alert escalates across Italy

On 22 June, Bologna, Bolzano, Brescia, Florence, Frosinone, Milan, Perugia, Pescara, Rieti, Rome, Turin and Verona were all under a level-3 warning, the maximum. The ministry defines this as "emergency conditions" that pose a risk to the entire population, not only vulnerable groups. By 23 June, Ancona, Venice and Viterbo will join the list, bringing the total to 15. On 24 June, Latina will also turn red, pushing the count to 16. Bari and Trieste remain at the orange alert level.

Emergency conditions (heatwave) with possible negative effects on the health of healthy and active people, not only on at-risk subgroups such as the elderly, very young children, and people with chronic diseases.

Temperature records under threat

Meteorologists warn that the heat will intensify through the weekend. Milan is forecast to surpass its all-time June record of 37°C, reaching at least 38°C. Florence could hit 41°C by Monday 29 June. Rome and other Tyrrhenian cities will see peaks of 37–38°C, with the urban heat island effect making it feel even hotter. Nighttime offers little relief: thermometers will struggle to drop below 24–25°C across the Po Valley, with some nights staying at 26–27°C, a phenomenon now routinely described as "super tropical nights."

Health services under strain

Emergency departments in large Italian cities have recorded a 10–15% increase in visits, according to Fabio De Iaco, former national president of the Italian Society of Emergency Medicine (Simeu). He noted that while there is no alarm, the rise is noticeable. The most affected are elderly people with multiple chronic conditions, but De Iaco also highlighted a newer pattern: people with psychiatric fragility are increasingly turning to emergency rooms, which often serve as a substitute for missing community support networks. Hospitals have activated "heat codes," preferential pathways for patients suffering from heat-related illnesses.

There is no alarm, we can estimate this increase at 10–15% in emergency departments of large cities.

Europe swelters

France and Germany are at the epicentre of the continental heatwave. Temperature anomalies of 15–17°C above the seasonal average are being recorded, with maximums reaching 42–43°C in parts of France. Paris could see 40°C. In Germany, several cities are also bracing for 40°C. The hot air mass has crossed the Channel, pushing London's forecast to 35°C, a level that will strain British urban infrastructure. Spain is also experiencing exceptional heat.

What is driving the heat

The heatwave is powered by a vast subtropical anticyclone, named Caronte, which is compressing and heating the air as it settles over the continent. This follows an earlier high-pressure system, Cerberus. The combination of an already hot air mass and compression heating is producing temperatures up to 15°C above normal in France and Germany, raising comparisons with the deadly 2003 summer. The heat is also fuelling instability: violent thunderstorms with hail are possible along the Alpine and Apennine ranges through Thursday, with local spillovers towards the Tyrrhenian coast.