Spain's eastern city of Valencia set a new temperature record on Thursday as the country baked under its third heatwave of the summer.

The mercury soared to 46.8 degrees Celsius (116.2 Fahrenheit) at Valencia airport, shattering the previous record of 43.4 Celsius set on July 6, 1986, state weather agency Aemet said on social media.

The centre of the Mediterranean port city was emptier than usual as many people stayed indoors to shelter from the heat, or escaped to the countryside or nearby beaches.

Those who did venture outside used fans and umbrellas to guard themselves against the scorching sun, or cooled themselves with water from fountains.

"This summer has been horrible... we cannot live in our apartment," Valencia resident Nazim Ali told AFPTV.

The local government opened an air-conditioned shelter to allow homeless people to escape the heat and access water, food and showers.

"At night we use the air-conditioning and a fan," said Roberto Gimenez, another resident. 

"During the day we try to leave the house as late as we can if we don't have work to do, and go to the beach."

The record for the highest temperature in Spain -- 47.6 degrees Celsius --- was registered on August 14, 2021, at Aemet's weather station in La Rambla in the southern province of Cordoba.

The heatwave affecting most of central, southern and eastern Spain is expected to ease on Friday.

Scientists say heatwaves have become more likely due to climate change. 

As global temperatures rise over time, heatwaves are predicted to become more frequent and intense, and their impacts more widespread.