Setúbal, Évora, Beja and Faro are under a yellow warning on Tuesday due to the forecast for rainstorms that could be locally heavy with hail followed by thunderstorms, the Portuguese Institute of the Sea and Atmosphere (IPMA) said.
The yellow alert for these four areas will be in effect today from 9:00 am to 9:00 pm, according to IPMA.
A Yellow Alert is issued by IPMA whenever a risk situation arises for certain weather dependent activities.
IPMA predicts periods of very cloudy skies on the mainland today with showers and thunderstorms especially in the southern region and a slight drop in maximum temperatures on the west coast.
The forecast also indicates generally light winds from the east quadrant, gradually shifting from the north quadrant, and the possibility of patchy fog or morning mist.
Minimum temperatures will range from 14 degrees Celsius (in Bragança) to 19 (in Portalegre and Faro), and maximum temperatures will range from 26 (in Guarda) to 33 (in Santarem and Evora).