According to the IPMA website, the districts of Viana do Castelo, Braga, Vila Real, Bragança, Porto, Aveiro, Viseu, Guarda, Coimbra, Castelo Branco, Lisbon, Setúbal, Leiria and Santarém are already under a yellow warning today, also due to the cold weather.

These districts have a valid warning until 9am on Wednesday due to the "persistence of low minimum temperature values", explains IPMA.

According to information from IPMA, the districts of Faro, Beja, Évora and Portalegre join the other 14 during the early hours of Wednesday and the yellow warning will be in effect in these four districts until 9am on Thursday.