BORDEAUX, France (AFP) — Two children were found dead in a car in France on Monday as the country experienced the hottest day yet in its latest heatwave, with temperatures forecast to reach 43 degrees celsius.

The two victims, ages two and four, were found dead in their family’s car in a residential parking lot in the south-eastern town of Carpentras, where temperatures had been forecast to reach a maximum of 39°C.

“The causes of death are yet to be determined but the heatwave is the leading line of inquiry,” said local prosecutor Helene Mourges.

France, for the first time, issued its highest heat warning across half the country for Monday, with forecasters warning the extreme weather episode could end up being as serious as a 2003 heatwave that claimed the lives of nearly 15,000 people nationwide.

The children are just the latest casualties to have been reported during the heatwave.

Three elderly people died in their homes as a result of the heat in south-western France on Sunday, according to local authorities.

And 13 people drowned across the country at the weekend, a civil defence official said, urging against unsupervised swimming to cool off.

Temperatures had been set to rise to a maximum of 43°C (109°F) in the south-western city of Bordeaux and 39°C in Paris on Monday afternoon, weather service Meteo-France said.

Overnight temperatures of 25.3°C in Bordeaux and 24.2°C in the capital broke records for the month of June, it said.

Several cities, including Tours and Poitiers in western France, experienced their hottest night on record, topping 24°C

More than 1,350 of the country’s 60,000 schools closed on Monday while another 4,042 adjusted their teaching hours, the education ministry said, updating a previous tally.

Other schools have suggested that parents keep their children at home or pick them up at lunchtime.

A primary school teacher in the Bordeaux region, who asked to remain anonymous to speak freely, told
AFP she was alarmed that the authorities were not taking measures to cool down schools.

“Last week it was 32°C in the classroom,” she said.

“It’s only going to get worse, while the supermarket across the street is cool and air-conditioned,” she added.

“Everyone thinks it’s normal but one day we’re going to end up teaching in the aisles of the supermarket.”

On Monday morning Paris regional authorities urged residents to stay at home, warning disruptions were expected on public transport.

France is experiencing its second heatwave this year, after an unusually hot spell in May that shattered records across half the country.

Scientists have shown that recurring heatwaves are a clear marker of global warming, primarily caused by burning coal, oil and gas — and warn they are set to become more frequent, longer, and more intense.

Meteo-France says that of the 51 heatwaves recorded nationwide since 1947, some 34 have occurred since 2000 and 26 since 2011.

Scientific studies estimate more than 70,000 people died across 16 countries in the exceptional temperatures Europe experienced in 2003, with France and Italy the hardest hit.