Victoria Faucanie, the chief marketing officer for Beaumarly, a Paris-based restaurant, hotel and club group, said that when her company bought the building housing the restaurant Café Français over a decade ago, one dining room had air conditioning but the other did not. At the time, it wasn’t an issue because temperatures weren’t as high as frequently or as persistently as they are now.

“With this high temperature now, we are closing half of the restaurant, so we are losing a lot of money,” Ms. Faucanie said. “We realized that we need to have AC everywhere.” She added that the restaurant is in talks to have it next year.

Paige Dacanay, 31, visiting Madrid from San Diego for the summer, said she doesn’t leave her rental apartment without two fans — one electric and one hand fan — and on the hottest days, she has taken up to three cold showers. “I was expecting not to have a ton of AC, but actually living here without it is extremely humbling,” she said. “You just have to get comfortable being hot.”

Renske Schuitmaker, 34, visited her home country, the Netherlands, from Nairobi during the late June heat wave. Ms. Schuitmaker, who was pregnant during her trip, said she had to leave her rental and stay with relatives who had air conditioning in Amsterdam, where temperatures got well into the 90s. Dutch authorities said that across the Netherlands, where air conditioning is uncommon, the June heat wave caused around 480 deaths.

Pamela Minucci, 64, and Robert Wilson, 65, who were visiting London from Connecticut for their daughter’s wedding, found themselves looking for places to sit in the shade. At one point, the couple sat at an air-conditioned pub showing a cricket match for hours. Asked if they followed the sport, Mr. Wilson chuckled. “We did that day,” he said.