ULTRA-VIOLET rays could hit maximum radiation levels on Friday and Saturday across the country, warns the State meteorological agency, AEMET.
The scale runs from 1-11, and Friday and Saturday could see UV radiation hitting levels of 10 and 11 everywhere except in Galicia and Cantabria.
Worst-hit areas will be the centre and south of Spain and the islands, although the east coast is also greatly at risk.
UV radiation, when it is at high levels, can cause serious skin burns which are disfiguring, and may lead to skin cancer.
The World Health Organisation has warned all those who venture outside to use sun cream of at least factor 15, and to stay out of direct sunlight over the lunchtime period.