A heatwave enveloped much of Spain on Sunday, driving temperatures to extreme levels and sending locals and tourists scurrying for shade and cooling waters.

National weather office AEMET issued heat warnings for most of the country, with the mercury expected to rise above 40 degrees Celsius (104 degrees Fahrenheit) in Madrid and the southern city of Seville for the second day running.

Spain's first bout of extreme heat of the year is forecast to spread east on Monday before easing. Only a sliver of Spain's northern Atlantic coast will be spared. Spain's highest temperature on record is 49 degree centigrade.

Some sought respite from the scorching heat in the air conditioned galleries of Madrid's Prado museum, whose collection includes works by Rembrandt, Rubens and El Greco.

"We thought this would be a good plan for a day like today," said Rosa Alfageme, 44, queuing to enter the museum with her husband and six-year-old daughter.

"It's like this every year, we almost forget," Alfageme told AFP, adding the family does not have air conditioning at home.

Others headed to parks or to municipal swimming pools. Tickets for all the capital's 19 outdoor swimming pools were sold out on Sunday. Capacity was limited due to virus safety measures.

"You have to go outdoors and look for shade," said Antonio Martin, a 64-year-old building supervisor who sought refuge from the heat with his family at Madrid Rio, a vast park that runs along the Manzanares River that has three large areas with water jets.

Children and adults splashed themselves in the fountains and cafe terraces along the river were packed.

"It's hot but it's bearable. With a beer everything is solved," said 69-year-old pensioner Soledad Gimenez at the park.

The authorities advised people to drink water frequently, wear light clothes and avoid prolonged exposure to the sun.

Meanwhile firefighters said they had brought a wildfire under control which had been burning since early Friday near the town of Jubrique in the southern province of Malaga.

The blaze affected 350 hectares of pine trees, local officials said. Meteorologists said the temperature could climb as high as 44 Celsius in the Guadalquivir valley near Seville on Sunday.