In a statement, the IPMA said that the districts of Porto, Setúbal, Viana do Castelo, Lisbon, Leiria, Aveiro, Coimbra and Braga are under alert due to the "persistence of high maximum temperature values".

The yellow warning will be in force at least until 6:00 pm today.

The IPMA predicts that especially the North and Centre regions will remain under “extremely high” weather severity until Wednesday, with the risk of rural fires ranging from high to maximum.

“The severity of the weather will remain extremely high” on “the 17th and 18th, in a large part of the territory, especially in the North and Centre regions, where the PIR [rural fire danger] will continue to be in the highest danger classes: high, very high or maximum”, said the IPMA, in a note published on its website.

The statement, valid until 18:11 today, states that the meteorological fire danger index calculated daily by the IPMA, which reflects the meteorological severity in the spread of rural fires, “has shown extreme values, proving the adversity of the current meteorological conditions”.

“In addition, the dryness index of dead fuels is very high, exceeding the average value for this time of year in a large part of the territory”, pointed out the IPMA, informing that the danger of rural fires was, in all municipalities on the mainland, “in the three highest danger classes” and “with 70% of municipalities in the very high and maximum classes” on Monday.

Since Saturday, the mainland territory has been “under the influence of an easterly flow, which intensified” on Monday and which “will remain intense” today, “in the North and Centre regions”.

“The values ​​of relative humidity are extraordinarily low, with values ​​of 10% or lower being recorded even in places close to the coast, such as in the regions of Aveiro, Porto or Viana do Castelo”, revealed the IPMA.