Between 8pm Tuesday night and 1am Wednesday morning, firefighters were called out to scores of small floods in homes and on the streets of Lisbon.
In all, around 50 cases were reported, also in the neighbouring areas of Sintra, Cascais, Loures, and Vila Franca de Xira.
No significant damage or injuries to people were caused.
According to the Civil Protection Agency’s website, the districts of Porto, Santarém and Setúbal were also affected by minor floods.