Portuguese health authorities have issued a weather alert, advising the public to take extra care as temperatures are forecast to exceed 40 degrees Celsius (104 Fahrenheit) in some southern parts of the country.

The General Directorate for Health recommended staying out of the sun Monday between 11 a.m. and 5 p.m. Authorities also warned of a high risk of forest fires in wooded areas of central and northern Portugal.

Official statistics show that after an uncommonly dry winter and spring, almost 54 percent of the Portuguese mainland was enduring extreme or severe drought at the end of May. With little rainfall in June, that percentage is expected to rise.

Neighboring Spain was also facing a heat wave as a mass of hot air from Africa flowed north to Europe.