PARIS, France (AFP) — More than half of France’s population was dealing with scorching temperatures on Friday, according to AFP’s calculations, with hundreds of schools adapting their timetables to keep students out of boiling classrooms.

Nearly 36 million French people — more than one in two — were affected by an orange heat alert issued by the weather office, the second-highest such warning urging residents to be “very cautious”, according to a calculation based on population figures from the national statistics agency.

The heatwave prompted 784 primary and secondary schools out of the country’s 60,000 teaching establishments to adjust their hours, including 150 that closed completely, said Education Minister Edouard Geffray.

France’s national weather agency has warned the heatwave would be “widespread, prolonged and intense”.

Temperatures were expected to peak at around 40C in some regions between Sunday and Tuesday.

Although astronomical summer does not begin until Sunday, this is already France’s second heatwave this year, following an unusually hot spell in May that shattered records across half the country.

France experienced its hottest spring this year since records began in 1900, with the average nationwide temperature over March to May around 1.7C above the norm.

Scientists warn that heatwaves in Europe are becoming more frequent as a result of climate change.