The Viana do Castelo district is at high risk of exposure to UV radiation.

On Friday, the risk will remain very high on the mainland and in the Madeira archipelago.

For the Azores archipelago, IPMA predicts very high levels today for the island of São Miguel, high for Faial and Flores, and moderate for Terceira.

The ultraviolet radiation scale has five levels, between extreme and low risk.

For regions at extreme risk, IPMA recommends avoiding exposure to the sun as much as possible.