Italy’s Ministry of Health declares red heatwave alert in 16 cities, including Milan and Rome, as schools close in UK.

Much of Western Europe is bracing for another day of a sweltering heatwave that has smashed temperature records in many countries and left tens of thousands of people without power in France.

The extreme weather is being driven by atmospheric and circulation patterns that keep hot air trapped in place for days, causing the mercury to slowly rise, as global warming exacerbates these factors, experts said.

France’s national temperature indicator – an average of daytime and nighttime temperatures across 30 stations – reached 29.8 degrees Celsius (85.64 degrees Fahrenheit) on Tuesday, the hottest since measurements began in 1947.

The heatwave caused the country’s first major power outage of this latest bout of extreme weather after a heat-related incident with a transformer left about 68,000 households on Wednesday without electricity in the northwestern department of Finistere, authorities said.

While teams worked through the night to fix the issue, which took place late on Tuesday, power is not expected to be restored in full until the end of Wednesday at the earliest.

Up to 106,000 clients of the French power network were left without power by late Tuesday as the scorching temperatures strained infrastructure built before man-driven climate change made heatwaves longer, more frequent and more intense, according to scientists.

Sales of fans and air conditioners, meanwhile, skyrocketed in a country where most buildings are not designed to deal with extreme heat.

Added to the 31 departments currently on orange alert, more than 90 percent of the French population is exposed to extreme heat with temperatures of 39C to 41C (102.2F to 105.8F) expected on Wednesday from Brittany to Paris and in much of the southwest.

Hundreds of British schools planned to close or close early this week because of the heat while many train services were reduced to avoid heat-related problems on the rail lines.

The Met Office, the United Kingdom’s weather agency, issued a heat warning for Wednesday and Thursday with forecasts suggesting June’s all-time daily temperature record could be broken.

Temperatures of about 37C (98.6F) are expected in southern England and up to 35C (95F) in southeast Wales.

The peak of the heatwave is now forecast for Wednesday and Thursday when highs could reach 39C (102.2F) in London or southern England.

Conditions are expected to ease by Friday, the Met Office said.

Italy’s Ministry of Health declared a red heatwave alert in 16 cities on Wednesday, including Milan and Rome.

Eastern Europe to be hit next

In the coming days, the heatwave is expected to extend into Eastern Europe.

Poland’s weather service issued high-level heat warnings for the western part of the country from Thursday to Saturday, predicting that temperatures could break the record of 40.2C (104.4F) set in 1921.

Croatia’s popular Adriatic coast was also put under red alert for Friday and Saturday.

Hungary, already under a second-level heat alert, said it was raising that to the maximum level from Saturday to Tuesday as temperatures continued to rise.

Some relief could start to come in Spain on Wednesday when the country’s State Meteorological Agency said temperatures would drop in most of the country.

By Wednesday afternoon, only parts of the Basque country in the north will still be marked red, and on Thursday, no part of Spain will be rated either red or orange.

But no quick relief is in sight across the rest of Western Europe.

From Wednesday until at least Friday, the central and southern Netherlands will be under a code orange for extreme heat while Belgium has placed the entire country under an orange heat alert starting on Thursday as a record-breaking heatwave looms, according to the newspaper Le Soir.