According to the Portuguese Institute of the Sea and Atmosphere (IPMA), Bragança, Vila Real and Guarda are under a red warning from 9:00 am today until at least 6:00 pm on Saturday, when the level will be reduced to orange, remaining in place throughout the weekend.

The orange warning due to hot weather is also active, at least until late Saturday afternoon, in Viseu and Castelo Branco.

The entire remaining mainland territory, with the exception of the districts of Lisbon, Leiria and Faro, is under a yellow warning.

The IPMA issues a red warning whenever there is an extremely risky weather situation, orange when the risk is moderate to high and yellow when there is a risk situation for certain activities depending on the weather situation.

A rise in maximum temperatures is expected today, especially on the coast of the North and Centre regions, and a slight drop in maximum temperatures in the Algarve's Sotavento region.

According to the IPMA, minimum temperatures will vary between 15º (Coimbra) and 21º (Faro) and maximum temperatures between 24º (Aveiro) and 40º (Castelo Branco).

Due to the forecast of hot weather, the Directorate-General for Health (DGS) recommended on Thursday a set of protective measures against the negative effects of intense heat, such as avoiding exposure to high temperatures, hydration and attention to the most vulnerable groups.

Other measures include drinking water, even when you are not thirsty, avoiding alcoholic beverages, and trying to stay in cool, airy or air-conditioned environments for at least two to three hours a day.

You should also avoid direct exposure to the sun, especially between 11:00 and 17:00, use sunscreen with an SPF of 30 or higher and reapply it every two hours and after swimming at the beach or pool.

You should wear light-coloured, light and loose clothing that covers most of your body, a hat and sunglasses with ultraviolet protection, and avoid activities that require great physical effort, especially sports and leisure activities, outdoors.

According to the DGS, you should choose the cooler hours to travel by car and avoid staying inside parked vehicles exposed to the sun.