'Coolcations' had another big summer. Here are the places travelers went

Extreme temperatures are driving travelers to seek cooler destinations. And there's a term for the trend: "coolcations."

Heat waves — which are increasing in frequency, duration and intensity, according to the U.S. Environmental Protection Agency — are affecting where people are choosing to vacation, especially during the hot summer months.

"Often, when we think of vacation, beaches and tropical escapes come to mind," a spokesperson for Expedia told CNBC Travel. "Coolcations however, are all about opting for destinations where the temperatures are more moderate, where you're packing a light sweater instead of a sun hat."  

From January to June 2024, flight searches increased 705% to Lapland, Finland, according to Expedia. The online travel agency said flight searches are also up to Canada, specifically Banff (65%) and Lake Louise (55%), its data showed.

The home rental website Vrbo reported that cooler places emerged among the top 40 most booked destinations this summer, a list which included Breckenridge, Colorado; White Mountains, New Hampshire; and Pocono Mountains, Pennsylvania.

Californian Stephanie Greitzer said she planned a family trip to Whistler this summer.

"We live in the San Fernando Valley in Los Angeles where we experience extreme heat for most of the summer, reaching highs well above 100," she said. "We want to be comfortable when we are traveling to experience all a city has to offer and take a break from the extreme heat at home."  

European cities, such as Rome and Madrid, top the list of popular summer destinations. But rising temperatures in southern Europe are hitting the summer travel season hard.  

This summer, Italian officials placed 12 cities under heat warnings, as temperatures hit triple digits in