Yellow alerts - indicating significant risk - for high temperatures were issued for Valencia, the islands of Menorca and Mallorca, Albacete, Ciudad Real, Cuenca, Toledo, Zaragoza, Teruel, Seville, Malaga, Huelva and Cadiz as well as Tenerife, La Palma, La Gomera and El Hierro in Canary Islands.
While in Cordoba, Granada, Jaén and the islands of Fuerteventura, Gran Canaria, Lanzarote were put on orange alert, signifying high risk.
The only regions to escape the heatwave sweeping across southern Europe were the north east and northern coast of Spain where rain, strong winds and storms were forecast from Galicia to Asturias, Cantabria and the mountainous Pyrenean zone.
Swathes of southern Europe sweltered over the weekend in a heatwave that has claimed several lives, cost billions in crop damage and is, scientists warned, a foretaste of worse to follow in coming decades.
At least five deaths in Italy and Romania and one in Spain have been attributed to the extreme conditions since the heatwave set in around the start of August.
Unusually high, sometimes unprecedented temperatures, are being recorded across an area spanning much of Spain and Portugal, southern France, Italy, the Balkans and Hungary.
The mercury has regularly risen above 40 degrees Celsius (104 degrees Fahrenheit) across the affected areas, exacerbating the impact of an extended drought and the lingering impact of a July heatwave which sparked wildfires that claimed 60 lives in Portugal.
Hospital admissions have spiked 15-20 percent in Italy, where at least three people have died.
Italians longing for the beach have dubbed the hot spell "Lucifero", or Lucifer, after the biblical archangel said to have been condemned forever to the flames of hell.
The latest victim was a woman whose car was swept away overnight by an avalanche of water and mud as humid conditions near the Alpine ski resort of Cortina d'Ampezzo broke into torrential rain.
That tragedy follows the deaths on Thursday of two pensioners caught up in wildfires in the central region of Abruzzo and near Matera in the south of the country.
In Spain a 51-year-old man died as a result of the heat on the Mediterranean island of Majorca.
150,000 weather deaths
Scientists meanwhile warned that deaths due to extreme weather in Europe could increase 50-fold from an estimated 3,000 per year recently to 152,000 by the end of this century - if global warming is not reined in.
Southern Europe will suffer most and heatwaves would account for 99 percent of the deaths, according to research conducted for the European Commission and published in The Lancet Planetary Health.