After weeks of extreme heat and what is already the fourth heatwave of the summer of 2026 northern Italy is now experiencing an abrupt change in weather. For today, Thursday 20 August, the Italian Civil Protection Agency (Protezione Civile) has issued a severe weather warning for eight regions, involving intense thunderstorms, hail, heavy rain and wind gusts of up to 100 kilometres per hour. The warning applies in particular to those currently travelling in northern Italy and northern Tuscany, as the combination of weeks of accumulated heat and an approaching Atlantic weather system is expected to produce an unusually intense storm situation.
What the Civil Protection Agency expects today
As the Dipartimento della Protezione Civile sets out in its official bulletin for 20 August, an orange alert (moderate criticality) is in force for large parts of Lombardia. Further parts of Lombardia and seven other regions are under a yellow alert (ordinary criticality): Piemonte, Trentino-Alto Adige, Veneto, Friuli-Venezia Giulia, Emilia-Romagna, Liguria and Toscana. The warnings relate both to the risk of thunderstorms and to the risk of hydrogeological instability, such as landslides and flooding in smaller watercourses.
The meteorological backdrop is an Atlantic weather systembringing cooler and unstable air that, upon meeting the warm and humid air mass over Italy, triggers severe convective phenomena. The first precipitation has been active over Piemonte and Lombardia since the early hours of the morning and is spreading during the course of the day into Liguria, the autonomous provinces of Trento and Bolzano, and later into Veneto, Friuli-Venezia Giulia, Emilia-Romagna and Toscana . According to regional meteorological services, two waves of storms are to be expected: a first in the morning and a second in the late afternoon and evening. Temperatures in the north are set to fall markedly, while remaining high in the south and in Sardegna.
Downbursts, hail and localised tornado risk
In addition to the official warnings from the Civil Protection Agency, specialist meteorological institutes such as the Italian consortium PRETEMP are highlighting concrete dangers posed by severe thunderstorms. As the specialist portal Meteoweb summarises in its analysis, the second-highest alert level for supercell storms applies to the upland areas between Piemonte, Lombardia, Veneto and Friuli-Venezia Giulia, with possible rainfall totals exceeding 300 millimetres within a matter of hours and a concrete tornado risk in certain zones.
Among the expected phenomena are hailstones with a diameter of between four and six centimetres and so-called downbursts, which are particularly destructive downward wind bursts produced by convective storms that can cause severe damage to vehicles, tents, parasols and vegetation within a short space of time. The area between the Po Valley and the pre-Alps is considered especially critical, owing to the collision of hot, humid air from the south with cooler air flowing in from the north.
Regional breakdown
For those wishing to assess the specific situation in their destination region, the Protezione Civile provides clear details. As the news agency Adnkronos sets out in a detailed breakdown of the alert levels, in Piemonte the areas most affected are those around Toce, Val Sesia, Cervo and Chiusella, as well as the northern Po Valley. In Liguria, the warning covers the central and eastern coastal basins and the eastern Padania basins. In Emilia-Romagna, the warning applies in particular to the mountain and hill areas of the Piacentino, Parmense and Emilia centrale. In Toscana, the areas affected include Lunigiana, Versilia, Garfagnana, Lucchesia and the basin of the river Serchio. Trentino-Alto Adige, Veneto and Friuli-Venezia Giulia are under a yellow alert across their entire territories.
Connection with the extreme summer
The current change in weather marks the possible end of one of the most intense heatwave periods in recent years in Italy. The weeks-long accumulation of heat and humidity in cities, which has defined the Italian summer of 2026 , simultaneously provides the energetic basis for the severe storm situation now threatening the country. Climate scientists have been pointing out for years that the increase in extreme heatwave periods is accompanied by a parallel rise in extreme rainfall and wind events, as higher air temperatures are able to retain more moisture, which is then released upon encountering cooler air masses. The current wildfire situation across Italy, from Sicilia to Friuli, is also directly linked to the weeks of prolonged drought.
What those travelling in the affected areas should now consider
For travellers in the affected regions, there are a number of practical recommendationsthat apply over the coming 48 hours. Cars should wherever possible not be parked under trees or in open fields, as hail and wind gusts can cause considerable damage. Walks in the pre-Alps and the Apennines are best postponed for today and tomorrow, as severe mountain storms can bring lightning strikes and sudden flash floods in stream beds. Particular caution is advised for campers and those staying in tented accommodation, as well as for driving on open motorways during the peak storm periods. Those on the water, whether on the northern Italian lakes, on the Adriatic coast as at Milano Marittima , or along the Ligurian coast, should check the weather forecast before setting out.
The The weather service of the Protezione Civile updates its bulletins twice daily; in addition, regional civil protection agencies such as the Arpa of the respective regions provide up-to-date information on precipitation and wind warnings. Once the weather system has passed, a marked improvement is expected from the weekend onwards, with a gradual return to more stable but noticeably cooler conditions in the north. This is likely to mark the final phase of the long summer that has defined Italy's holiday regions since the end of June.
