Belgium's Royal Meteorological Institute predicted it could reach 104 on Thursday — the highest temperature it has ever forecast since the institute's founding in 1833.
The number of deaths blamed on heat or fires rose to 38 Thursday, after Croatian police reported the death of an officer deployed to guard the U.S. Embassy in a Zagreb suburb.
The 41-year-old policeman died Wednesday of a heart failure likely caused by the heat, police said.
On Thursday, fires raging across Italy forced officials to close a state road on the Amalfi coast in the south and evacuate some homes as a precaution in Tuscany and the northwestern Liguria regions, the Civil Defense Department said. Scattered blazes were also reported in Lazio.
Water-toting helicopters and planes were dousing the flames, which have already destroyed hundreds of acres of woods and Mediterranean bush.
Weather experts from Italy's state-funded CNR research center said the heat wave was among the five worst in the last 150 years and would likely last until September.
Europe was hit by hot air from northern Africa rather than the usual weather patterns that come in from the Atlantic, said Capt. Alessandro Fuccello, from the Italian air force's meteorology office in Rome.
High-temperature records have been broken in several French cities, and London, where betters wagered on just how high the mercury would rise, registered its highest-temperature ever Wednesday — 95.7.
Wildfires, fanned by hot winds, were reported in Croatia, Greece, Spain, Portugal and France, as well as Italy. In the German state of Brandenburg, which surrounds Berlin, authorities said a total of 395,000 acres of forest had been closed to the public because of the danger of fires.
Few facets of life escaped the heat wave, which was particularly oppressive because air conditioning in homes and shops is uncommon in much of Europe.
On the Croatian island of Pag, residents were banned from washing cars, watering gardens or taking showers at beaches.
In Amsterdam, about 100 of 47,000 fans of the soccer team Ajax who came to an open-house day Wednesday received first aid after feeling sick, dehydrated or overheated.
And a British Airways Concorde was forced to make an unscheduled stop Wednesday in Gander, Canada, because hot air, with its higher pressure, meant more fuel was needed.
A highway swelled in Germany because of the heat, and trains were moving slower the last few days in Britain and Croatia for fear the tracks might buckle.
Other places, like Spain, are more accustomed to sizzling summers, although this hot spell has been exceptionally long. A high-pressure system has been hanging over southern Europe for more than two months.
Spanish TV and radio broadcasts were urging people to drink lots of water, limit exercise outdoors and wear loose-fitting clothing.
A hospital in eastern Belgium was giving patients free ice cream twice a day, but Belgian boat rental companies were suffering after kayaking was banned on several rivers with low water levels.
The stretch of Danube passing through the Balkans dropped so low that wrecks of World War II boats became visible.
Animals were suffering, too.
Tons of fish died in Croatia's fish ponds. In Birmingham, England, the National Sea Life Center sent a refrigerated van to an indoor ski center for a supply of snow to help otters stay cool.
In Rome, waves of hot air rolling through the largely deserted downtown made an afternoon stroll feel more like a trek through the desert.
Federico Abbett, 25, from Switzerland, was walking with other seminarians, all dressed in black, near the Pantheon.
"We're used to dressing in this garb, even when the temperature is so high. We drink a lot and we try to walk on the shady side of the street," Abbett said.
In an odd twist, Athens, notorious for almost unbearable summer heat, was being cooled by fierce northerly gusts known locally as the "meltemia." Some Athenians have taken to wearing long sleeves to ward off the evening chill.