This has left almost the entire continent under an orange alert, according to the Portuguese Institute of the Sea and Atmosphere (IPMA).
More than 50 municipalities in the districts of Faro, Portalegre, Castelo Branco, Viseu, Santarem, Bragança, Vila Real and Guarda are at the highest risk of fire.
The highest predicted maximum temperature will be reached in Evora and Santarem – 42 degrees Celsius.
In the Beja region the temperature will be 40 degrees, Portalegre – 39, Castelo Branco – 38, Vila Real – 36, Bragança and Viseu – 35, Guarda – 33 and Faro – 31.
IPMA also placed several municipalities in all districts of mainland Portugal, with the exception of Viana do Castelo, at very high fire risk.
IPMA estimates that fire danger will remain in some areas until at least Friday.
This risk, defined by IPMA, has five levels, from low to maximum. The calculations are based on air temperature, relative humidity, wind speed and the amount of precipitation over the past 24 hours.
Due to the heat, IPMA has issued an orange alert for 11 areas with an orange alert from today to Wednesday due to the hot weather forecast.
The areas of Évora, Setúbal, Santarém, Beja and Portalegre will be under orange alert from 9:00 this Monday until 18:00 on Wednesday.
The areas of Bragança, Viseu, Guarda, Vila Real, Castelo Branco and Braga will be under orange alert from 9:00 Tuesday to 18:00 Wednesday.
The areas of Porto, Faro, Viana do Castelo, Lisbon, Leiria, Aveiro and Coimbra will be under yellow alert from 9:00 this Monday until 18:00 Wednesday due to the persistence of very high maximum temperatures.
The Madeira archipelago is also under a yellow warning until 6pm on Wednesday due to hot weather.
An orange warning is issued by IPMA whenever a “moderate to high risk meteorological situation” occurs, and a yellow warning when there is a risk situation for certain activities depending on the meteorological situation.
IPMA forecasts hot weather for this Monday on the continent with partly cloudy to clear skies, generally light winds from the eastern quadrant, sometimes strong in the northern and central highlands until mid-morning, and an increase in maximum temperatures expected to be accentuated over the coast and the southern region.
Minimum temperatures will range from 14 degrees Celsius (in Coimbra) to 23 degrees Celsius (in Portalegre), while maximum temperatures will range from 28 (in Aveiro) to 42 degrees (in Evora and Santarem).
In Funchal, temperatures will range from 23 to 27 degrees, and in Porto Santo from 21 to 26 degrees.