US vs. Europe: Same heat, very different danger

Another extreme heat wave is building over western Europe, and while the temperatures may sound like just another summer day for many of us in the United States, that heat usually has deadly results on the other side of the pond.

Temperatures in some parts of France and Spain could surge past 104 degrees Fahrenheit (40 degrees Celsius) next week. Paris may crush its record high for June, 99.7°F (37.6°C), says The Weather Company’s senior director of meteorological operations, Leon Thomas. Temps in London could get above 98°F. 

(MORE: Paris heat wave frenzy)

In a U.S. city like Phoenix, Arizona, those same numbers are nothing extraordinary. So why is the impact and potential danger so much higher in Europe?

It’s estimated that 175,000 people die from heat-related causes in Europe, the highest of any region, according to a 2024 report from the World Health Organization, and it essentially comes down to how Europeans, live, build and cool down – or can’t cool down.

Almost no air-conditioning

“We don’t have anywhere near as much air conditioning (as the U.S.), certainly in homes,” explained Chris Almond, a Weather Company senior meteorologist in the UK. 

It’s estimated that 90% of homes in the United States have AC, compared to about 19% across Europe. Almond notes that in the UK, AC becomes a need around 24-25°C (75-76°F) and Europe’s average summer highs have historically stayed just below that line, but climate change is now pushing temperatures over that threshold.

“It’s kind of on the tipping point,” he said.

Almond also points out that northwest Europe is surrounded by seas and oceans: “We’re surrounded by water, so when we get heat, there’s a lot of available moisture around which raises the humidity … so that makes it feel hotter than it is.”

It can feel "up to 5 degrees, maybe even nearly 10 degrees warmer than it actually is," Almond adds. So you may see the same thermometer reading as U.S. heat, but it’s much harder on the body.

Old homes that become ovens

Most of Europe’s older cities and homes were designed to hold heat during frigid winters, but in a heat wave they can become ovens.

“Our traditional problems have been with keeping warm, particularly in the winter, it's cool and damp and it rains a lot," Almond says. "So our buildings, particularly homes are generally designed to keep heat in, they've all got central heating, but not many places are designed to keep the heat out.”

Roughly 3 in 4 European homes predate modern thermal standards, according to numbers from the EU Covenant of Mayors.

Nights that never cool and an older population

Midnight temperatures in France may stay around 26-28°C (79-82°F) with calm winds so there'll be little relief for days next week, explained Thomas.

Summer nights are when the body usually recovers from the intense heat of the day, but climate change, combined with urban heat traps, mean temperatures aren’t falling after sunset.

(MORE: Why nighttime temps matter in a heat wave)

Older people are also more vulnerable to extreme heat. It’s estimated that 22% of the European Union’s population is 65 or older, versus about 16% of the U.S. population.

The new normal?

Intense summer heat is looking like the new normal for Europe. Almond notes.

“The last three summers over Europe have been the hottest three on record — 2024 first, 2023 second, 2025 third … and we've got this summer to come. We could be looking at another record year."

So the same temperatures that are routine in the U.S., could once again prove deadly across the continent.