It's not just the cities. Extreme heat is a growing threat to rural America.

Vox

24-06-2025

is a correspondent at Vox writing about climate change, energy policy, and science. He is also a regular contributor to the radio program Science Friday. Prior to Vox, he was a reporter for ClimateWire at E&E News.
Summer has officially begun with a blast of scorching temperatures across much of the United States. The National Weather Service is warning of 'extremely dangerous heat' baking 160 million people under a heat dome stretching from the Midwest to the East Coast the rest of this week. It's already proven fatal.
But while this is the first real taste of extreme heat for Northeastern cities, parts of the country like Texas have been cooking since May. Alaska this month issued its first-ever heat advisory. Forecasters expect more above-average temperatures through the summer.
Related The Vox guide to extreme heat
Summers are indeed getting hotter, a consequence of the warming planet. As the climate heats up, the frequency and intensity of heat waves is increasing and their timing is changing, arriving earlier in the season.
But the damage from extreme heat isn't spread out evenly, and the more dangerous effects to people are not necessarily found in the hottest places. High temperatures often lead to more emergencies and hospital visits when they represent a big jump from a place's average, which means ordinarily cooler regions tend to suffer the worst harm from heat. That includes places like Alaska and the Pacific Northwest, where temperatures rarely climb higher than 80 degrees Fahrenheit and most homes don't have air conditioning.
Related This number can measure how dangerous a heat wave is for you
Now researchers have found that rural areas may suffer more under extreme heat than previously thought. A report from Headwaters Economics and the Federation of American Scientists found that more than half of rural zip codes in the United States, which includes some 11.5 million Americans, have 'high' heat vulnerability, a consequence not just of temperatures but unique risk factors that occur far outside of major cities.
The thermometers thus do not tell the whole story about who is likely to suffer from extreme heat — nor do the images, which tend to come from sweltering cities. But understanding the factors that worsen the harm of rising temperatures could help save lives.
What makes the countryside so vulnerable to extreme heat
The discussion around the geography of extreme heat tends to focus on the urban heat island effect. The concrete, asphalt, steel, and glass of dense urban areas act as a sponge for the sun's rays. Air pollution from cars, trucks, furnaces, and factories helps trap warmer temperatures over cities, and that hotter air, in turn, accelerates the formation of pollutants like ozone. On a hot summer day, a city center can be 25 degrees Fahrenheit warmer than the surrounding regions. And with so many people squeezed into these metropolitan ovens, it adds up to a massive health burden from extreme heat.
Related What American cities could do right now to save us from this unbearable heat
But far outside of downtowns, where homes and buildings get farther and farther apart, rural regions face their own long-running challenges that exacerbate the dangers of extreme heat.
A major factor: the median age of the rural population is older than in cities. That matters, because on a physiological level, older adults struggle more to cope with heat than the young. People living in rural communities also have double the rates of chronic health conditions that enhance the damage from heat like high blood pressure and emphysema compared to people living in urban zip codes.
Rural infrastructure is another vulnerability. While there may be more forests and farms in the country that can cool the air, the buildings there are often older, with less adequate insulation and cooling systems for this new era of severe heat. Manufactured and mobile homes, more common in rural areas, are particularly sensitive to heat. In Arizona's Maricopa County, home to Phoenix, mobile homes make up 5 percent of the housing stock but account for 30 percent of indoor heat deaths.
Even if rural residents have air conditioners and fans, they tend to have lower incomes and thus devote a higher share of their spending for electricity, up to 40 percent more than city dwellers, which makes it less affordable for them to stay cool. That's if they can get electricity at all: Rural areas are more vulnerable to outages due to older infrastructure and the long distances that power lines have to be routed, creating greater chances of problems like tree branches falling on lines. According to the US Census Bureau, 35.4 percent of households in rural areas experienced an outage over the course of a year, compared to 22.8 percent of households in urban areas.
Sparsely populated communities also have fewer public spaces, such as shopping malls and libraries, where people can pass a hot summer day. Rural economies also depend more on outdoor labor, and there are still no federal workplace heat regulations. Farmworkers, construction crews, and delivery drivers are especially vulnerable to hot weather, and an average of 40 workers die each year from extreme heat.
The health infrastructure is lacking as well. 'There is a longstanding healthcare crisis in rural areas,' said Grace Wickerson, senior manager for climate and health at the Federation of American Scientists. There aren't always nearby clinics and hospitals that can quickly treat heat emergencies. 'To really take care of someone when they're actually in full-on heat stroke, they need to be cooled down in a matter of minutes,' Wickerson said.
The Phoenix Fire Department has now started using ice immersion for heat stroke victims when transporting patients to hospitals to buy precious time. But rural emergency responders are less likely to have tools like this in their ambulances. 'In Montana, which has not traditionally seen a lot of extreme heat, you would not have those tools on your truck and not have that awareness to do that cooling. When you see someone who has to also then travel miles to get care, that's going to worsen their health related outcomes,' Wickerson said.
Emergency response times are generally much longer in rural areas, sometimes extending more than 25 minutes. People also have lower incomes and lower rates of insurance far from cities. Hospitals in rural areas are closing down as well. So when severe heat sets in, rural healthcare systems can get overwhelmed easily.
Looking at data from the Centers for Disease Control and Prevention and the US Census Bureau, Wickerson and her collaborators mapped out how all these underlying factors are converging with extreme heat. They found that 59 percent of urban zip codes and 54 percent of rural zip codes are highly vulnerable to extreme heat as defined by the CDC's Heat and Health Index, meaning they are much more likely to see health problems from extreme heat. So while rural areas may be cooler, the people living there face heat dangers comparable to those in much hotter cities, and geographically, they cover a much wider expanse of the country.
Rural areas across the US are facing major threats from extreme heat. Headwaters Economics/Federation of American Scientists
So while temperatures out in the sticks may not climb to the same peaks they do in downtowns, urban heat islands are surrounded by an ocean of rural heat vulnerabilities.
There's no easy path to cooling off
There are ways to reduce the dangers of scorching weather across vast swaths of the country, but they aren't fast or cheap. They require big upgrades to infrastructure — more robust energy delivery, more shade and green spaces, better insulation, cool roofs, and more energy-efficient cooling.
Countering extreme heat also requires bigger structural investments to reverse the ongoing rural healthcare crisis where a doctor shortage, hospital closures, and longer emergency response times are converging. But the Republican budget proposal will do the opposite, cutting healthcare access for millions of Americans that would, in turn, lead to dozens of hospitals closing down, mainly in rural areas.
Protecting people from dangerous heat also demands policy changes. Most states don't have any worker protections on the books for extreme heat. The Occupational Safety and Health Administration is in the process of creating the first federal heat safety standard for employers, requiring them to give employees breaks, water, and shade when it gets hot. But it's not clear how strong the final regulation will be given that the Trump administration has been working to weaken rules across the board.
Cities and local governments could also impose rules that prevent utilities from shutting off power to customers during heat waves, similar to regulations that limit heat shutoffs during the winter.
But there are limits to how much people can adapt to hotter temperatures. Even places with a long history of managing heat are seeing more deaths and hospitalizations as relentless temperatures continue to mount. That means curbing the ongoing warming trend has to be part of the solution as well, reducing greenhouse gas emissions to slow climate change.