Data shows 23 million Americans live in places most at risk of extreme heat

Skyline on hot day

It was another blazing hot summer for many parts of the country. The intensity and duration of heat waves are reaching record highs, worsened by climate change. But it’s not just the presence of heat that is concerning; who and where this heat is affecting matters too.

Similar to flooding and other climate events, certain people and places are dealing with more extreme environmental and economic impacts from heat. Younger and older residents, especially in lower-income households and communities of color, continue to suffer the most direct heat impacts. Neighborhoods with more pavement and less green space tend to radiate more heat. And with increased heat comes increased energy costs, as households turn up their air conditioners to combat the unsafe temperatures.

Combining data from the Centers for Disease Control and Prevention (CDC), the Department of Energy, and the Census Bureau, this brief highlights the significant heat-related risks and costs in the country’s metropolitan areas. The results are alarming: 23 million residents live in neighborhoods that experience intense heat, face high energy costs, and house vulnerable residents least able to cope with these impacts.[i]

With the number of extreme weather days predicted to get worse—including more extremely cold days in many regions as well—this analysis is another sobering reminder of the urgency to adapt to new climate realities. As such, the brief closes with recommendations for policymakers on designing communities better able to withstand extreme temperatures as well as managing benefit programs that reach those most in need.

Heat is a challenge in many metro areas

More intense and longer-lasting heat waves—defined as persistent periods of unusual or extremely hot days—are becoming increasingly common. And while the intensity and duration of heat waves vary across different metro areas, hotter summers are now commonplace nationally.

Analyzing temperature data from the CDC shows that one-fifth of U.S. metro area residents—or about 60 million people—face more than 76 days with temperatures over 90 degrees each year. Not surprisingly, many of these metro areas are located in the nation’s Sun Belt, from Las Vegas and Tucson, Ariz. to Dallas and Houston. But even metro areas farther north, such as Kansas City, Mo. and Richmond, Va., are managing more extreme heat. Almost double the number of residents (118 million) face at least 26 days with temperatures over 90 degrees each year, including many southeastern metro areas that also contend with high humidity.[ii]



Although 90-degree days have been common in many of these areas for some time and it is important to recognize the local variation in individual markets (i.e., parts of the Southwest are accustomed to extreme heat), the reality is that more people in more places are dealing with more heat, especially as longer-lasting and more intense heat waves become increasingly common.

High energy costs are a problem, especially for younger and older residents with lower incomes

As the number of scorching days continues to rise, many people do not have the economic means to withstand the higher temperatures. As Brookings’s Carlos Martín recently explained, energy bills have long been too expensive for many of America’s most economically vulnerable households—and a 15.5% jump in electricity prices only made the situation worse this past summer.

On average, U.S. households spend about 3% of their income on energy bills—to cool and heat their homes, power appliances, and more. But many households can spend 6% or more instead, which researchers consider a high “energy burden.” Analyzing Department of Energy cost data shows that about 10.5 million people living in metro areas fall into this category; considerably more people (almost 64 million, or about a quarter of the total metro area population nationally) are spending at least 4% of their income on energy bills. And these figures do not even fully reveal the hardships for residents in the lowest income brackets.

The scope of this challenge is expansive, affecting both northern and southern metro areas. For example, East Stroudsburg, Penn. and Gadsden, Ala. are the two metro areas that have the highest share of residents struggling with high energy burdens, at around 39% each.


Within the larger population that is struggling with high energy burdens, there are specific demographic groups that face greater exposure to heat risks, including people younger than 5 or older than 60. (These groups are specific targets for the Low Income Home Energy Assistance Program, discussed later.) Tracking individuals by both income and age, then, becomes another critical dimension to identify at-risk neighborhoods.


Our analysis of census tract data shows that almost 9 million residents under 5 or over 60 are living in poverty across all metro areas nationally—or about 12% of the population for these two demographic groups. In some areas, this rate can be 21% or higher, demonstrating a severe concentration of lower-income, vulnerable residents.

Twenty-three million metro area residents live in places that face these challenges all at once

Any one of these three risk factors—temperature, energy costs, and residents’ age and income—can put people in harm’s way and place an economic and environmental strain on a metro area. However, the places most at risk (and most in need of support) are those where all three occur at the same time. By simultaneously examining heat stress, energy burdens, and poverty rates among vulnerable populations, we can see which metro areas—and which tracts within them—are most at risk.

Nationally, almost 23 million metro area residents live in tracts that fall in the top 40% for each of the three challenges. That means that in these tracts, residents experience more than 26 days with temperatures over 90 degrees, the average household pays over 4% of their income in energy costs, and over 12.7% of the under-5 or over-60 population lives in poverty. Most concerning, 1.9 million metro area residents live in census tracts that fall in the top 20% for all three categories.[iii]

These tracts are spread across the country, painting a national picture with an alarming number of at-risk hotspots. And in many of these metro areas, the at-risk census tracts house a large portion of the total metro area population. For example, 71% of Sumter, S.C. residents live in at-risk census tracts, as do 52% of Jackson, Tenn. residents. 


Public policy must continue to adapt to new climate realities

This analysis reveals that far too many American neighborhoods combine vulnerable populations, high energy costs, and generally high temperatures. To help these people and places adapt to our new climate realities, there are three responses that policymakers should consider.

To reduce energy cost burdens, federal policymakers should permanently grow the Low Income Home Energy Assistance Program (LIHEAP). This program provides funds for vulnerable households to offset energy costs for cooling in the summer, in addition to assistance for winter heating, energy crises, and weatherization improvements. Congress has perpetually underfunded LIHEAP, and even the recent funding infusions via the Infrastructure Investment and Jobs Act and the Inflation Reduction Act will not meet the long-lasting and growing gap.

Not only is LIHEAP underfunded, it’s also poorly coordinated between federal, state, and local levels. LIHEAP operates as a block grant program, in which the Department of Health and Human Services coordinates with states and other eligible local entities (e.g., tribes) to reach those in need. This distributed system means that the various LIHEAP administering agencies often operate differently, causing uncertainty and inefficiency in the program. A 2021 report from the Government Accountability Office suggested that the use of consistent electronic data verification could improve national coordination, ultimately enhancing the program’s integrity, improving administrative operations, and expediting the application process. Other researchers highlight the inherent connection between housing cost burdens and energy burdens, and they advocate for a centralized organization responsible for both housing and energy affordability, which would bring the disparate programs, applications, and procedures together under one roof.

Policymakers can also improve buildings within at-risk neighborhoods by investing in their physical condition and modernizing regulatory codes. For example, Brookings’s Carlos Martín described how the Inflation Reduction Act will help cover the cost of energy and weatherization upgrades in the country’s lowest-income households—which has the dual benefit of reducing fossil fuel emissions and monthly energy costs. State and local officials can launch their own programs to make heat pumps, window upgrades, and other investments more competitive for both residential and commercial building owners. They can take cues from efforts like those in Kansas City, Mo., where the local electricity provider has partnered with the Salvation Army to provide an array of upgrades. Similarly, California’s Public Utilities Commission is using cap-and-trade funds to finance heat pump installation incentives, with a particular focus on low-income utility customers.

Finally, to protect the residents and businesses in neighborhoods facing the most extreme heat, policymakers should rethink how we plan and build communities. A lack of tree cover dramatically impacts the levels of heat residents experience, and unsurprisingly, low-income areas with the most at-risk populations have the fewest trees. Relatedly, the hardscape materials that often pave over green space in American metro areas further turn up the heat. Understanding these impacts, places such as Los Angeles and Phoenix have taken action by offering tax incentives for installing green roofs and high-albedo sidewalks (which reflect rather than absorb heat), and by committing to plant 1,800 trees along highly trafficked “cool corridors,” respectively.  In the long run, metropolitan planners and builders must reduce outward patterns of growth, which would preserve more lands with forests and other natural processes that can serve as carbon sinks.

These are just a sampling of the steps needed to help at-risk communities as temperatures continue to rise. What ties them together is a recognition that policymakers cannot expect past designs to protect against today’s climate realities. America must adapt, because our longer, hotter summers aren’t going anywhere.


[i] We combined data from the CDC, the Department of Energy, and the Census Bureau to identify specific regional and sub-regional risks nationally across 380 metropolitan statistical areas and 60,000 tracts.

[ii] While high humidity increases health risks, we chose the number of days over 90 F as our metric to stay consistent with extreme heat analysis previously conducted by the Department of Health and Human Services.

[iii] In these tracts, residents experience more than 76 days with temperatures over 90 degrees, the average household pays over 6% of their income in energy costs, and over 21.7% of the under-5 or over-60 population lives in poverty.