An unusual summer scorcher or a new normal?

Some travelers aren't waiting to find out if this year's heat wave in southern Europe is an anomaly or part of a longer-term pattern caused by climate change.

Tom Marchant, co-founder of the London-based luxury travel operator Black Tomato, told CNBC that his company has already seen a shift in interest from travelers hoping to avoid the searing summer heat.

"We're seeing strong interest and desire to take advantage of the Scandi summer," he said. "Scandinavian destinations like Finland, Norway, Sweden, Iceland are seeing a pronounced rise from the sales front."

'Scandi summer' trend

Interest in visiting the Mediterranean dropped by 10% from June to November this year, according to data published by the European Travel Commission. The summer of 2022 was Europe's hottest on record.

On the flip side, summer bookings to Scandinavia are up 37% from last year, Marchant said, citing his company's data.

"And we expect this will continue to climb," he said.   

A "Scandi summer" trend is evident among summer home renters too, according to Expedia Group.

German travelers, in particular, are shifting their vacation searches on Vrbo northward, with interest in southern Norway rising 35% in the first two weeks of July from the same period in June, according to Expedia Group.

Company data also showed German interest in vacation homes went up in the Swedish southern counties of Skane and Blekinge.

Elsewhere, vacation home searches from across Europe went up noticeably in:

• Edinburgh, Scotland — +20%
• Riga, Latvia — +25%
• Tallinn, Estonia — +25%

Across Europe, home rental interest in the southern Swedish province of Smaland rivaled those in the popular Spanish island of Tenerife — and exceeded those in the Italian beach town of Rimini, according to Expedia Group.

Shifts in Spain

Spain is the most popular travel destination in the European Travel Commission's poll of more than 6,000 European travelers. But travel interest is shifting there as well, according to Expedia Group.

Vacation home searches to popular spots like Costa Blanca, Costa Brava and Mallorca remained steady from June to July, according to company data, but home rental interest climbed across Spain's northern coast.

Home searches went up in Costa Verde, Costa de Cantabria and the culinary powerhouse autonomous community known as the Basque Country, data showed.

Alternatives to the Greek islands

Temperatures have dropped since, but just last month, wildfires in Greece forced tens of thousands of people to be evacuated from the islands of Rhodes, Corfu and Evia — while some were still in their swimwear.

The Greek islands are among Europe's top summer travel spots, but Marchant said some people are turning to another set of islands much farther north.

"The Lofoten Islands in Norway are especially appealing to our clients with families as an ideal alternative to Greece and Croatian islands," he said, especially "for those who don't want the intense heat of the Med."

Others are skipping island trips entirely, he said.

"Destinations like Canada, U.S. National Parks and European hidden gems like Slovenia have also proven especially popular."

Italy in the fall

Summer may be synonymous with travel for many, but the threat of heat waves, wildfires, flooding and hurricanes are leading some to push their annual trips to other seasons.

More people are choosing "shoulder season travel," which often has lower hotel rates, more availability and better temperatures, Marchant said.

"In Italy's southern heel, Puglia and Sicily are performing strong, but especially in shoulder season, the fall," he said. "You will still have warm and sunny weather well into October given its close proximity to North Africa, but fewer crowds and a more laid-back experience."

Trading beaches for mountains

Because of rising summer temperatures in Europe, more people are seeking out higher elevations and mountainous terrains, Marchant said.

"We're seeing renewed interest in the Dolomites, and the Swiss and Austrian Alps, in places like Lucerne and Solden," he said.

Even countries that many travelers assume are unbearably hot have cool spots at higher altitudes, Marchant said.  

"Morocco is a great example," he said.

Marrakech may be toasty in the summer, but the Atlas Mountains can be cooler — and even get brisk at night, he said. Plus, the summer is low season in Morocco, so it will be quieter and most likely of better value too, he added.

Most soldiering on

Travelers who have already made travel plans seem to be staying the course.

Cynthia Nerangis, founder of LemonLime Travel, which specializes in travel to Greece, Italy and France, told CNBC Travel that her clients are sticking with their plans to visit Greece this summer — from Athens to the Cyclades and Crete.

And bookings increased this year at the train, bus and flight booking company Omio, but cancellations remain low, said Peter Tomlinson, its vice president of data.

"Despite extreme heat, wildfires and increased flight prices, Omio only saw a cancellation rate of 3% of tickets in southern Europe," Tomlinson told CNBC.

A representative of the insurance company InsureMyTrip said it hasn't seen a noticeable uptick in calls or emails from customers wanting to change or cancel plans because of the heat. Similarly, Squaremouth, another travel company, said it hasn't heard from any travelers wanting to cancel, or make claims about, trips affected by the heat wave.