Thunderstorms were reported on Thursday into Friday in Sicily, Calabria and Puglia, where several people were injured when lightning struck a beach near Salento. Three were taken to hospital, including a 13-year-old boy said to be in serious condition.
Elsewhere in Puglia, rescuers pulled a young child from a car stuck in floods in the town of Grottaglie, near Taranto, as rain turned the streets into lakes.
#Maltempo nubifragio a #Grottaglie #Taranto— Polizia di Stato (@poliziadistato) August 24, 2018
Tra le persone soccorse dai poliziotti del Commissariato anche una famiglia con un bimbo di 4 anni rimasti bloccati nell'acqua.
Per il bimbo nessuna paura, gli agenti l'hanno fatto passare come un gioco portandolo in giro in #Volante pic.twitter.com/4CR3Uo7SCC
In Sicily, meanwhile, firefighters were called out around 100 times overnight to rescue residents trapped in flooded homes, assist motorists and pump water from roads.
Sudden, heavy rainfall was also expected in the north, in Piedmont, Lombardy, Veneto, Friuli Venezia Giulia and Emilia Romagna.
Italy's Civil Protection Department issued orange weather warnings for the regions of Friuli Venezia Giulia and Calabria from Friday afternoon, with another alert ordered to take effect in Lombardy on Saturday.
Most of Italy has been placed under less serious yellow alert for Saturday, the department said, with thunderstorms forecast the length of the country but especially in the north.
Temperatures everywhere are forecast to drop sharply over the weekend, according to Meteo.it, and could fall by as much as 14 degrees Celsius in the north-east, where parts of the mountains are expected to see snowfall.
The bad weather is set to continue on Sunday, followed by a rapid return of summer heat from Monday.