1. Sacramento, California
Sacramento might not get the attention that SoCal or the Bay Area does, but its heatwaves are just as brutal—and often deadlier, according to Anna Skinner of Newsweek. Inland California cities like Sac can trap heat without the coastal breezes that help moderate things. Forecasters are predicting more days above 105°F this summer than any on record for the region. The delta breeze that locals rely on for relief? It’s becoming less predictable.
Urban sprawl and a limited tree canopy are adding to the misery. Officials are urging residents to stay indoors during peak heat and check on neighbors. The city is also grappling with increased wildfire risk, which can compound health issues by adding smoke to already hot air. For a city known for its “golden hour” sunsets, this summer might have more than its share of sweltering days.
2. Houston, Texas
Houston’s humidity is already legendary, but this summer it’s being cranked up to eleven, Justin Ballard of the Houston Chronicle warns. Climate experts say the combination of heat and Gulf moisture could make Houston feel more like Bangkok on its muggiest day. The number of heat index days over 110°F is expected to hit a new record. And because the city sits just above sea level, stagnant air can trap pollution and heat longer than other places.
The city is preparing by expanding its heat mapping project to better understand the hottest neighborhoods. There’s a clear link between income level and heat exposure here, and officials are focusing relief efforts accordingly. Power outages during heat events are a growing concern after previous storms crippled the grid. Houstonians are being urged to prepare early and take warnings seriously.
3. Phoenix, Arizona
Phoenix isn’t a stranger to scorching temperatures, but this summer could push things into dangerous new territory, according to Holly Bock of AZ Family. With multiple triple-digit days already hitting in May, meteorologists are warning of prolonged heatwaves stretching deep into July. Urban development has amplified the city’s heat island effect, making it harder for nighttime temps to cool things down. That means less relief, more strain on AC units, and higher risks for vulnerable populations.
Arizona’s largest city has been investing in heat resilience efforts, but the growing population makes it harder to keep pace. Heat-related illnesses are already spiking earlier than usual, raising alarms for emergency services. Summer monsoons typically offer some relief, but forecasts suggest they might arrive late or weaker this year. For locals, the best defense is shade, hydration, and keeping a wary eye on rising temperatures.
4. Las Vegas, Nevada
Vegas is prepping for what could be one of its hottest summers on record, Amy Graff of The New York Times warns, and that’s saying something. Nighttime lows are staying stubbornly high, a trend that’s been building over the past decade. The city’s rapidly growing suburbs and reflective buildings trap heat, making it feel like the Strip never cools off. Local officials have already started rolling out cooling centers ahead of schedule.
Tourists might think of Vegas as a desert oasis, but extreme heat can catch visitors off guard. Emergency rooms often see upticks in heatstroke cases, particularly among people walking long distances outdoors. With more events scheduled downtown this summer, city planners are working to improve shaded areas and water availability. But locals know: when it hits 115°F, even the slot machines start to feel like ovens.
5. Miami, Florida
It’s not just the heat in Miami—it’s the humidity that’ll knock the wind out of you. This summer, record ocean temperatures are pushing heat indexes into the danger zone more frequently. South Florida’s tropical climate has always been hot, but the rising dew points are making it increasingly intolerable. The city’s public health officials are especially worried about how this will impact outdoor workers and the elderly.
Miami has declared heat a public health emergency for the first time ever, launching a new Chief Heat Officer position. Cooling strategies like misting stations and shaded bus stops are part of the plan, but they may not be enough. Coastal residents also face added complications from power outages due to tropical storms. If you’re in Miami this summer, prepare for sweat—lots and lots of it.
6. Austin, Texas
Austin saw record-breaking heat last year, and 2025 is shaping up to be more of the same—or worse. With limited rainfall so far this year and increasing drought stress, the city’s reservoirs are lower than usual. Combine that with sprawling asphalt and limited tree canopy, and you’ve got the perfect recipe for extreme heat exposure. Even the lakes that offer a summer escape are seeing higher-than-normal water temperatures.
The city is focusing on outreach to unhoused populations, who are among the most at risk. Cooling centers and free transportation to them are being promoted earlier than in years past. The city’s electrical grid has also been tested repeatedly during heatwaves, raising concerns about blackouts. Austinites love their outdoor festivals, but this summer, shade and hydration are non-negotiables.
7. Atlanta, Georgia
Atlanta’s canopy of trees—once its saving grace—has been shrinking thanks to development, and the city’s feeling it. This summer, temperatures are projected to average 3 to 5 degrees above normal, a significant jump for the region. The combo of heat and Southern humidity is a recipe for stress, particularly for older residents and those with preexisting conditions. School districts are already reviewing outdoor activity policies for the fall.
The city has invested in cooling stations and is increasing outreach through community organizations. But with more people moving to Atlanta every year, the strain on infrastructure is growing. Roads, transit systems, and emergency response teams are being tested more frequently by extreme weather. If you thought Hotlanta was just a nickname, this summer might make it feel literal.
8. New Orleans, Louisiana
New Orleans is bracing for a summer where the heat might rival the hurricanes in terms of danger. High humidity combined with record sea surface temperatures means heat indexes could hit 120°F. The French Quarter may be festive, but it offers little shade or airflow during a heatwave. Many older homes still rely on window units or fans, making sustained high temps especially dangerous.
City officials are preparing for “wet bulb” temperatures—the point where the body can no longer cool itself through sweating. This kind of heat is rare but increasingly plausible, and it’s deadly. Community centers are being converted into 24-hour cooling shelters, with transportation assistance for those in need. As climate change continues to shift the South’s heat dynamics, New Orleans is on the front lines.
9. Denver, Colorado
It may seem counterintuitive, but Denver is quickly becoming a heatwave hotspot. At a mile high, the thinner atmosphere doesn’t block UV rays as well, and heat can feel more intense. This summer, persistent heat domes are predicted to hover over the Rockies, raising average highs by several degrees. Snowmelt is occurring faster than ever, reducing the natural cooling effect of mountain runoff.
The city has expanded its tree-planting efforts, but shade remains limited in many neighborhoods. For a city known for its outdoor lifestyle, this heat poses serious risks for hikers and bikers. Trail closures due to extreme conditions are likely to increase this summer. Even at elevation, climate change is turning up the thermostat.
10. Seattle, Washington
Seattleites usually count on mild summers, but those days may be over. A brutal heatwave in 2021 shattered records, and this year could be even worse according to early forecasts. The Pacific Northwest is seeing unprecedented dry spells paired with higher-than-normal temps. With limited AC infrastructure—less than half of Seattle homes have central air—the city remains vulnerable.
The city is actively working on resilience plans, including retrofitting public buildings as cooling centers. But with wildfire smoke also in the mix, indoor air quality becomes an issue, too. Schools and daycares are beginning to adjust schedules in anticipation of dangerous heat. If you’re heading to Seattle thinking it’s sweater weather, pack sunscreen instead.
11. Los Angeles, California
Los Angeles is preparing for another punishing summer of extreme heat, especially in its inland valleys. While the coastal breeze helps some neighborhoods, places like the San Fernando Valley regularly see highs well over 100°F. Heatwaves are lasting longer, and overnight temperatures are failing to drop enough for meaningful recovery. That spells trouble for public health systems and vulnerable communities.
The city is expanding its tree canopy in under-shaded areas, but the effort takes time. Rolling blackouts remain a concern, particularly during peak demand on hot afternoons. Street-level heat is made worse by reflective surfaces and traffic congestion. For a city so tied to the outdoors, the heat is turning basic errands into endurance tests.
12. Chicago, Illinois
Chicago is often thought of as a winter city, but its summer heatwaves are no joke. This year, meteorologists are warning of prolonged heat events with humidity that could rival Southern cities. The last time the city faced this kind of heat threat was during the deadly 1995 heatwave. That disaster exposed just how dangerous urban heat can be, especially for elderly residents in poorly ventilated buildings.
Since then, the city has taken big strides in emergency planning, but aging infrastructure remains an issue. Cooling centers are opening earlier, and Chicagoans are being asked to check in on neighbors. Water restrictions and potential power grid issues are also on the radar. Summer in the Windy City may not come with a breeze this year.
13. Salt Lake City, Utah
Salt Lake City has been experiencing longer and hotter summers, and 2025 is set to push the limits. With less snowpack and earlier melts, the region is entering the dry season already behind on water. Record temperatures in June are setting the stage for an unusually intense July and August. And at over 4,000 feet elevation, sun exposure is more intense.
The Great Salt Lake’s continued shrinkage is another compounding factor—dry lakebeds contribute to heat and poor air quality. The city is working on both heat mitigation and water conservation, but resources are stretched thin. Residents are being urged to limit outdoor activity during peak hours and take heat alerts seriously. It’s a sharp contrast to the ski-town image many still have of the city.
14. Raleigh, North Carolina
Raleigh is seeing climate shifts that are moving it into a new heat category entirely. Summers are getting hotter, longer, and more humid, with nighttime lows staying uncomfortably high. This year’s heat index forecasts are already pushing into extreme danger levels for several weeks in July and August. That’s pushing local officials to reevaluate public service hours and school schedules.
The city is leaning into community partnerships to improve access to cooling resources. Water utility infrastructure is also under strain due to increased demand and shrinking reservoirs. With fewer breezes and more stagnant air, the discomfort can linger for days. Residents who once relied on summer thunderstorms for cooling relief may find that pattern breaking down.
15. St. Louis, Missouri
St. Louis is getting hit with the double whammy of heat and humidity this year. Situated at the crossroads of major weather systems, the city is prone to prolonged heatwaves. Forecasters are predicting multiple weeks with temps in the upper 90s and low 100s, combined with humidity that pushes the heat index well beyond safe levels. The infamous 2006 heatwave is being used as a benchmark for emergency response planning.
Low-income neighborhoods face the brunt of this crisis due to limited access to AC and green space. The city is working to expand tree cover and distribute cooling resources through local nonprofits. Power outages remain a risk, particularly during thunderstorms that can knock out older grid systems. For a city rich in history, this summer might be one for the record books.
16. Boston, Massachusetts
Boston may not come to mind as a heat hotspot, but that’s changing quickly. This summer is forecasted to bring more 90+ degree days than any in recorded history. The city’s old brick buildings and limited AC infrastructure make heatwaves especially taxing. Schools, in particular, are struggling to adapt to these new conditions, prompting early dismissals in past years.
The city is investing in reflective roofing and more tree cover to fight the heat island effect. But many residents, especially in older neighborhoods, still rely on fans or window units. Public pools and splash pads are seeing record demand, with city services stretched to accommodate. For a town more used to snowstorms, this summer might be its hottest challenge yet.
