According to the Institute, the south coast of Madeira will remain under a red warning, the most serious of a scale of three, due to the persistence of high values of the maximum temperature until 20:00 today.
The forecast points to maximum temperatures of around 30 degrees Celsius in the Madeira archipelago for the next few days, which on the southern slopes can reach 35 degrees.
The rest of the archipelago is under a yellow and orange warning for hot weather.
On the mainland, the districts of Vila Real, Bragança, Viseu, Guarda, Castelo Branco, Santarém, Portalegre, Setúbal, Évora, Beja and Faro remain under yellow warning due to the heat until 6 pm on Wednesday.
The IPMA predicts for today on the continent cloudy or clear skies, obscured by smoke particles, coming from the fires in Canada, sometimes strong wind on the west coast and a drop in temperature in the south region, especially on the west coast.
The minimum temperatures will fluctuate between 16 degrees Celsius (in Viana do Castelo and Braga) and 24 (in Castelo Branco) and the maximum between 27 degrees (in Aveiro) and 40 (in Évora).
The orange warning indicates a meteorological situation of moderate to high risk and the yellow one is issued by the IPMA whenever there is a risk situation for certain activities dependent on the meteorological situation.
With regard to exposure to ultraviolet radiation (UV), the IPMA placed the island of Madeira today at extreme risk and on Wednesday at very high risk.
According to the IPMA, the island of Porto Santo, the 18 districts of mainland Portugal and the Azores archipelago have very high levels of exposure to UV radiation.
The ultraviolet radiation scale has five levels, between extreme and low risk.
For regions at extreme risk, the IPMA recommends avoiding exposure to the sun as much as possible.
As for regions with very high risk, the IPMA advises the use of sunglasses with UV filter, hat, t-shirt, parasol, sunscreen and to avoid exposing children to the sun.