Scientists said the heatwave, which began on June 20, was the worst recorded in the continent where the climate is changing faster than the global average.
Temperatures were peaking in France and the United Kingdom, where records for June have been broken.
But in Italy, the heat was expected to intensify into the weekend, bringing the northern hemisphere summer's first readings of 40C.
Paris hit a June record of 40.9 C on Wednesday.
Even though temperatures were expected to ease, authorities braced for more casualties.
"There will be consequences in terms of the number of additional deaths," French Health Minister Stephanie Rist told reporters.
Across the continent, cultural landmarks have been forced to close and farming has suffered.
In the UK, doctors said the hot weather was affecting critical equipment such as MRI scanners in hospitals.
Paris police asked organisers of major events, including the Solidays music festival, to cancel.
Organisers of the Pride festival said they would reschedule.
In Belgium, a planned re-enactment this weekend of the 1815 Battle of Waterloo - which resulted in the defeat and exile of French emperor Napoleon Bonaparte - was cancelled as a result of the heatwave.
Extreme heat caused the surface of the A2 motorway in Germany to buckle and rupture over several lanes on Thursday evening.
In Austria, the rail company warned that train tracks could buckle in the coming days.
Even Sweden was not immune from the ball of heat rolling across the continent; a cargo train derailed late on Thursday as high temperatures caused track buckling, stopping traffic between Stockholm and the country's second-biggest city Gothenburg.
The UK's Met Office extended a red heat alert, covering a large area of southern and eastern England, into a third day for the first time, while a temperature of 36.9 C meant the UK record for the hottest June day had been broken on three successive days.
Hundreds of schools remained closed and London's emergency services said calls for help were up 50 per cent.
A teenage boy died after entering a lake in central England, police said.
A red alert was issued for almost the whole of the Netherlands and many schools were closed as temperatures up to 40C were expected, inflicting misery on visitors.
"I was expecting 'hot' but not this hot," 20-year-old New Zealander Ruby Prescott said, hoping for cooler air inside the Rijksmuseum, Amsterdam's main art gallery.
Electric fans flew off the shelves in the UK, and Asian air conditioning manufacturers reported a European sales boom.
Most homes in normally chilly to mild northern Europe are not built to withstand such heat but rather to keep it in.
According to the most recent data from the International Energy Agency, issued in July 2025, household ownership of air conditioning in Europe remains relatively low, at about 20 per cent.
The heatwave, which has pushed temperatures as much as 18C above their seasonal average, according to the Reuters Climate Monitor, is being driven by a weather pattern known as an Omega block.
This traps a bulging ball of hot air over regions for extended periods, with cooler air on its fringes.
The present heatwave, which moved up from the Iberian Peninsula towards western Europe, will begin shifting by the end of the month, hitting central Europe and the Balkans, the World Meteorological Organisation said.
For scientists, sweltering night-time temperatures are of particular concern.
Temperatures overnight have not dropped below 22C, depriving the human body of the ability to recover and shed the excess heat from the day, and which can drive excess deaths, John Kennedy, WMO Head of Climate Information said.
