France's Health Monitoring Institute said the heatwave that struck most of the country in the second half of last month -- France's hottest July record -- had contributed to the deaths of 112 people.

Twelve of those who died suffered hyperthermia -- heatstroke or sunstroke -- while working in the sun and most of the rest were elderly.

This year, there has been no repetition of the massive loss of life caused by the last major heatwave in 2003, when in France alone 15,000 people died.

Meanwhile a 31-year-old man became the 13th victim of the heatwave that continues to sweep much of Spain.

The man, the youngest victim to date of the hot weather, died at Terrassa near the eastern city of Barcelona, Catalan regional government officials said on Thursday. He had been taken to hospital on July 27 suffering from heatstroke.

The Greek authorities did their bit for overheated citizens on Thursday, opening 25 air conditioned centres in Athens as temperatures in the Greek capital reached 38 degrees Celsius (100 degrees Fahrenheit).

The health service warned old people and those suffering from heart problems not to go out and urged people to look out for old people who live on their own, as forecasters warned temperatures would climb even higher on Friday.

Separately, the Greek environment ministry said high temperatures and the lack of wind meant ozone levels in some areas of Athens were at risk of exceeding safe limits.