The blaze broke out on Thursday in the mountains near the town of Almonaster la Real, 120km (75 miles) northwest of the city of Seville.
It has already scorched 100 square kilometres (38.5 square miles).
Sixteen helicopters and eight planes are helping more than 500 workers tackle the blaze, including firefighters and army emergency personnel who worked around the clock this weekend.
Juan Sanchez of the Andalusia Forest Fire Department said weather conditions were playing a key role, adding: “It is very difficult to say when the wildfire will be under control.”
The wind dropped overnight making their task a little easier, but the authorities expect the fire will be fuelled by strong winds later on Sunday.
Crews were also struggling to reach all affected areas because of the rugged terrain, officials said.
A further 70 people were evacuated on Saturday because of a wildfire in Mula, a small town in Spain’s southeastern region of Murcia, while firefighters are also trying to extinguish two wildfires in the western region of Extremadura.
