The wildfires, among the many devastating mainland Greece this summer, were previously contained to the island’s mountainous region, but strong winds and dry conditions pushed the flames toward the coastal villages. Nearly 2,000 people, including locals and tourists, were evacuated by sea on Saturday. 

In recent weeks, record-breaking global temperatures and heat waves over the United States, Southern Europe, and Northern Africa have disrupted plans of those looking to enjoy their vacation months in the first summer since the pandemic years. 

For instance, thousands of tourists had to cancel or flee their vacations in Sicily and Sardinia, where temperatures reached 115° F earlier this month and wildfires threatened major towns. 

In some areas, merely spending time outside can be dangerous, whether for vacationers or locals. 

“No one is outside ever. Anything you do, you’re inside,” Andi Davis, an inventory manager in Phoenix, told Fortune. “You don’t even want to swim because the water in the pool is uncomfortably warm.” 

Temperatures in Phoenix have been above 110° F for 28 days and counting. Even saguaro cacti are collapsing under the heat.

People are spending as much time indoors and near the air conditioning as possible, Davis said. But when it’s necessary to venture outside, even driving is uncomfortable.

“If you have a car with a leather interior, your skin is burning. The seatbelt metal burns your skin. The air conditioning in people’s cars is always breaking down,” Davis described. 

“The only thing worse than being outside is how hot your car is inside,” Jared Thornton, a bartender in Tallahassee, told Fortune. “Sauna is an understatement. It’s a lot worse.”

And the heat is spoiling summer traditions. Whereas most Floridians usually flock to the beaches, Thornton said, the current heat wave makes it a miserable place to be with no way of cooling down.

Local businesses are feeling the effects of the heat, too. 

“We’ve had customers leave because our AC cannot keep up,” Thornton said about his bar. “Our business is super slow—when during the summer it would be a great place to be—but right now I don’t blame anyone for not coming.”

Summers like these may be here to stay, experts say.

This extreme heat would have been “virtually impossible” were it not for human-caused global warming, according to a new analysis released on Tuesday by the World Weather Attribution, a group of researchers that conducts studies on extreme weather events.

“Unless the world rapidly stops burning fossil fuels, these events will become even more common and the world will experience heat waves that are even hotter and longer-lasting,” the analysis said.

This year’s June was the hottest ever on record globally, and July is on track to do the same. 

The deadliest weather phenomenon

Thirty-five percent of the U.S. population—roughly 114.2 million people—live in areas that are reaching dangerous heat levels, according to the heat index. 

The heat index is a measure used by the National Weather Service that combines the air temperature with humidity, indicating how hot it feels outside, or the “real feel.” It is also used to determine the bodily risks associated with extreme temperatures. 

Severe heat is by far the deadliest weather phenomenon, according to the National Weather Service. On a 30-year average basis, heat-related fatalities are nearly twice that of flood-related fatalities and over triple that of hurricane-related fatalities.

Extreme temperatures can lead to heat-related illness, including heat stroke, heat exhaustion, heat syncope (fainting). The most serious of these illnesses is heat stroke, which occurs when the body can no longer control its temperature, according to the Centers for Disease Control and Prevention. Heat stroke is possible in heat indexes above 103° F and highly likely at 125° F and higher.

“The body’s temperature rises rapidly, the sweating mechanism fails, and the body is unable to cool down. When heat stroke occurs, the body temperature can rise to 106° F or higher within 10 to 15 minutes,” according to the CDC. “Heat stroke can cause permanent disability or death if the person does not receive emergency treatment.”

Numerous heat-related deaths within the U.S. have been recorded since the start of July, although determining a precise count is difficult since the symptoms vary and can worsen a patient’s underlying medical condition, the CDC says.