Portions of Spain are undergoing their swellest May ever with temperatures beyond 40C in some places, according to the state weather agency, AEMET.
The agency published heat premonitions in 10 district for Saturday, saying it could be "one of the most intense" heatwaves in years.
The city of Jaén in southern Spain registered its uppermost ever May temperature of 40C on Friday.
Climate change is making hot spell more common and more extreme.
Spain's inopportunely warm spring weather is an outcome of empty talk coming from North Africa, bring about temperatures to rise up to 15C in excess for this time of year.
The hardest-hit districts are Andalusia in the south, Extremadura in the south-west, Madrid and Castilla La Mancha in the centre and Aragon in the north-east.
Spain's health ministry exhort inhabitants to drink enough of water and to keep to cool places when necessary. It also admonished people to decrease physical exercise.
"This year it seems to have gone directly to summer, but we have to keep going," Madrid road sweeper Rocio Vazquez, 58, told Reuters news agency.
Tourists were also feeling the heat.
"I was expecting a little bit cooler, fresher weather," Eric Solis, 32, told Agence France-Presse during a trip to Madrid from the US. It is "not too convenient for tourists", he added.
Nightly temperatures have also been unexpectedly towering, residual above 25C in numerous districts on Friday night. In Jaén, the minimal temperature of 25.9C was the uppermost ever unregistered in mainland Spain.
Analysts say that hot spell are ppssibly to become more common and more extreme across the globe, as international temperatures rise up. Their influence is also possibly to be more general.