Northern Italia: the heat lasts longer – 12 hours a day

The scorching summer of 2026 got underway during one of the most extreme heatwaves of recent years in Italia. Between 15 and 25 June, the average temperature exceeded 30°C for more than ten hours a day in many northern cities, according to data collected by 3bmeteo and analysed by Il Sole 24 Ore. In Milan, the extreme heat showed no sign of letting up for almost 12 hours a day around the summer solstice.

As already indicated by the latest Sole 24 Ore Climate Index, which compiles climate data on 105 regional capitals from 2008 to the present day, heatwaves are on the rise. And today’s update, incorporating data from the past two weeks, adds a further dimension: as well as being more frequent, these heatwaves are lasting longer, with temperatures exceeding critical levels for several hours a day. And prolonged exposure is affecting cities in the north in particular.

In 2008, on hot days, temperatures exceeded 30°C on average for six hours a day, which is effectively one hour in every four. In 2025, there were more than nine ‘hot hours’ a day in almost all the major cities surveyed, particularly those in the north. And data from June 2026 confirm the long-term trend in Milan, Bologna and Turin. ‘The duration of exposure,’ explains Alessandro Conigliaro, a meteorologist at 3bmeteo, ‘has increased, particularly in the north, due to the axis of the anticyclonic ridge that has settled over western Europe. The subtropical high-pressure system is driving the peak heat between Spain, France and northern Italia’. As early as the end of May, temperatures 10–15°C above normal were recorded across western France, England and Wales. The second, more severe heatwave began on 22 June, and since then night-time temperatures in France have not fallen below the thresholds.

In northern cities, temperatures exceeding 30°C are more frequent, partly due to the smaller daily temperature range. ‘The urban heat island effect keeps temperatures high at night,’ explains the expert from 3bmeteo, ‘and the distance from the sea means the climate cannot be moderated, reducing daily temperature variations.’ In coastal cities, in fact, there are fewer hours above 30°C thanks to sea breezes.

Prolonged exposure is particularly affecting Milan, where ‘extreme heat’ lasts for nearly 12 hours a day. “‘As the area is highly urbanised,’ adds Conigliaro, ‘it is more severely affected by the anthropogenic effect of heat absorption by asphalt and concrete surfaces, especially after sunset when the temperature drops much more slowly than in other urban centres or in the suburbs.’