Storms rolled in all over the nation except for southern Italy, with the most intense rainfall in the north-east and centre.
Italy’s Civil Protection Department warned of thunderstorms and strong winds in the regions of Piedmont, Lombardy, Trentino-Alto Adige, Veneto, Emilia-Romagna, Tuscany and Marche.
Bathers in Marche were forced to flee from the beach as black clouds rolled in.
Areas from Milan and Genoa to Bologna and Rimini were at greatest risk for flash flooding and strong winds.
The storms brought a break from the heatwave which has roasted Italy over the past two weeks, with temperatures dropping into the mid or low 20s in the north.
But it remained hot and humid in many areas, including Rome, which had its first rainfall in several weeks but was back above 30˚C by the afternoon.
The Italian health ministry issued a red alert for extreme heat in Pescara, while lower orange alerts issued in Bari, Reggio Calabria, Palermo and Messina.
On Wednesday, the threat for severe thunderstorms will shift south and east, bringing relief to these areas.