The fire near Odemira began on Saturday and was driven south into the hilly interior of the Algarve, Portugal's main tourism region, by strong winds.
Former BBC correspondent Alastair Leithead, who lives around 16km (10 miles) south of Odemira in São Teotónio, knows how dangerous and fast-moving wildfires in Portugal's countryside can be.
With the flames once again raging minutes from his home, he told Radio 4's World at One programme the fires sent "everybody in this area into a real panic" on Monday but that things had calmed "a little" on Tuesday "simply because the wind has dropped."
He said commercial eucalyptus and pine forests in the area have been engulfed, adding: "It's wild country, there aren't roads going through them, so when the fires get into the valleys they burn fast and hard, and when the wind... gets going, it's a very dangerous thing to deal with.
In Spain, fires near the south-western coastal cities of Cadiz and Huelva and in the northern Catalonia region scorched more than 1,000 hectares (2,470 acres) in total on Saturday and Sunday.
Ruben del Campo of Spain's State Meteorological Agency told Reuters it was being caused by a large mass of hot, dry air from North Africa and would be "generally more intense, more widespread and a little longer-lasting" than the two that hit in July.