The latest updated information from the Institute of the Sea and the Atmosphere (IPMA) also places, as of Monday morning, the districts of Viana do Castelo, Porto, and Lisbon on an orange warning (the second most serious on a scale of four, Leiria, Aveiro, Coimbra and Braga due to maritime agitation.

According to the IPMA, the districts of Guarda and Castelo Branco will be, from 21:00 on Monday, under an orange warning due to the wind.

These two districts are from 23:00 today and Monday on a yellow warning due to snowfall.

In addition to Guarda and Castelo Branco, the other districts that will be, as of Tuesday under a yellow meteorological warning due to snow, are Coimbra, Bragança, Viseu, Porto, Vila Real, Viana do Castelo, Aveiro, and Braga.

The IPMA warns of disturbances caused in these 10 districts due to snowfall with accumulation and possible formation of ice, such as conditioned or closed roads, damage to structures or trees, and impaired local supplies.

On Saturday, the ANEPC urged the population to adopt preventive measures to defend against a “significant drop in temperature”.

The authority warned of the potential risks of this meteorological situation, namely “poisoning by inhalation of gases, due to inadequate ventilation in houses where heating such as fireplaces are used”.

The elderly, children, people with chronic pathologies and the homeless are the “most vulnerable” groups of people who need “special attention” to protect themselves from the cold weather, while motorists must adopt defensive driving and attention to the “slippery roads or the possible formation of sheets of water and ice”, they added.

The temperature will drop from today in mainland Portugal, and could reach minus five degrees Celsius in the interior North and Center by the middle of the week, the IPMA announced on Friday.