The warning due to the persistence of high values of the maximum temperature will extend until 21:00 today, then turn yellow until 18:00 on Wednesday.

The IPMA also placed the districts of Setúbal, Santarém, Portalegre, Castelo Branco, Guarda, Viseu, Vila Real and Bragança under yellow warning until 18:00 on Wednesday.

The archipelago of Madeira will be under an orange warning between 09:00 and 21:00 today, then it will change to yellow until 09:00 on Wednesday.

The orange warning indicates moderate to high risk weather situation and the yellow is issued by IPMA whenever there is a risk situation for certain activities dependent on the weather situation.

The IPMA predicts until Wednesday in the northern and central interior and in the southern region values above 30 degrees Celsius in most of the territory, being between 35 and 40 degrees in the interior south of the Tagus and in Beira Baixa, where they may reach 40 to 43 degrees.

The minimum temperature will also be high, with tropical nights (with the minimum being above 20 degrees) in several places in the center and south, especially in the Eastern Algarve region, where they may be close to 25 degrees.

At stake is, according to IPMA, a "joint action of an anticyclonic region between Western Europe and the archipelago of Madeira, and a depressionary valley that extends from North Africa to the Iberian Peninsula, originating the transport of a tropical air mass with the continental origin, which is favorable to a meteorological situation of hot and dry weather."

The IPMA said in a statement published on its website that the hot weather is expected to be more prolonged south of the Tagus and Beira Baixa, where a heat wave is expected to occur until Wednesday.