Over half of France's regions face red heat warnings as the nation prepares for extreme temperatures during a strengthening heatwave.

Parts of western France could see highs above 40C (104F) on Monday, with Bordeaux potentially reaching 42C according to forecaster Meteo-France.

The education ministry reported that 845 schools have closed entirely while another 1,800 are releasing students early, though over a million high school pupils still face oral baccalaureate exams.

Officials have cautioned against swimming in unsupervised lakes or rivers following 13 drowning incidents over the weekend.

A red alert represents the top warning level from Meteo-France and urges extreme caution amid potentially dangerous conditions.

Numerous additional regions remain under orange alerts, the second-highest tier, impacting an estimated 63 million people nationwide.

Rail operator SNCF advised vulnerable passengers to delay or skip journeys this week, and several Paris lines cut services on Monday because of the heat.

Belgium's rail network also canceled select peak-hour trains for Monday and Tuesday as record temperatures loom according to the IRM institute.

Madrid may reach 39C on Monday while Rome could hit 37C in Italy.

Red warnings apply across other western and central European areas including Germany and Switzerland from Monday plus Luxembourg from Tuesday.

Hot Saharan air moving northward traps heat over western and central Europe, potentially creating one of the longest heatwaves in recent years.

Many locations expect peak readings on Wednesday.

Meteo-France noted that of 51 heatwaves since 1947, 34 occurred after 2000 and 26 after 2011.

Spain's Aemet service warned of extremely high seasonal temperatures until Wednesday, five to 10 degrees above normal.

A red alert covers the Basque country where San Sebastian may climb to 40C, nearly double the typical value for this period.

The UK's Met Office issued a rare red heat warning for parts of England and Wales on Wednesday and Thursday with possible peaks near 38C (100F).

The nationwide event ban covers all state-organized activities to protect emergency services and let medical staff focus on vulnerable groups.

Three deaths partly linked to the heat were reported Sunday in the south-west Gironde region among people aged 80 to 95.

Health Minister Stephanie Rist stated on TV1 Info that many citizens will suffer and urged close monitoring of relatives and neighbors.

While western coastal areas face the highest readings, most of the country should see 36C to 40C, Meteo-France said.

The forecaster described the heatwave as widespread, long-lasting and intense with relief not expected before the weekend's end.