As Phoenix heads toward what could become its hottest year on record, Maricopa County is seeing a troubling shift in who is dying from extreme heat — and where.
Preliminary 2026 figures from the county suggest a larger share of heat-related deaths are happening indoors, particularly in homes where paying to use or repair air conditioning may be out of reach, according to KJZZ.
Here's what to know
County data shows 230 confirmed heat-related deaths this year, with another 567 cases still under investigation — 60% higher than last year's figures.
Heat-related deaths dipped slightly in 2024 — the first decline in a decade — and then fell 30% in 2025.
"We were really happy to see that decrease, knowing that every single one of these deaths is preventable," said Kelli Donley Williams, deputy director of the Maricopa County Department of Public Health.
Phoenix temperatures reached triple digits in mid-March, and the county linked nine deaths to that spring heat wave — an exceptionally early spike for the year.
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The city recorded 29 nights at or above 90 degrees in 2026, more than four times the 1991-to-2020 average.
One notable change was where those deaths occurred.
Preliminary county data puts the indoor share at 34% in 2026, compared with about 24% from 2023 through 2025.
County public health data shows many of these cases involve lower-income households that may not be able to afford to keep an air conditioner running or repair it if it stops working.
More background
Longer, hotter heat seasons increase the risk of dehydration, organ failure, and death, especially for people without stable housing or access to reliable cooling.
Extended heat also strains household budgets, forcing families to balance essentials such as food, rent, utilities, transportation, and medical care.
Lower-income Arizona households are feeling that strain especially sharply this year.
Jessica Berg, chief program officer with St. Vincent de Paul, a social services organization, acknowledged a worrying trend.
"Folks are really struggling," Berg told KJZZ. "We're just seeing that decrease in folks' ability to get food for themselves, and they're having to choose between food and rent and utilities, medical bills, transportation — all of it."
Dr. Jeff Johnston, Maricopa County chief medical examiner, warned that some of the most dangerous periods are not always the hottest afternoons, but the stretches when the heat never truly lets up.
"It seems to be those overnight lows that aren't getting below 90, particularly on consecutive days, that seems to be riskiest," he observed.
Jonathan Nelson, a Phoenix resident experiencing homelessness, described navigating a year of dangerously hot weather.
"I've been in the hospital because of the heat. I've been in kidney failure because of the heat. This heat this year is by far the worst year ever in Phoenix, Arizona, and I was born and raised here. It's horrible," Nelson said.
What's being done?
Local governments and community groups have expanded heat relief efforts across the region in response.
In 2026, the Maricopa Association of Governments' Heat Relief Network had more than 200 sites offering free water and indoor cooling, with most operating from May through the end of this month.
Phoenix City Council also approved more than $5 million for heat relief operations this year.
David Hondula, director of Phoenix's Office of Heat Response and Mitigation, reported that the city's downtown 24-hour heat relief site logged more than 37,000 visits since May and said those investments are making a difference.
Still, Donley Williams acknowledged that keeping those services in place could become more difficult. Much of Maricopa County's heat relief funding came from the American Rescue Plan Act, and that support expires at the end of the year.
Live operators for 211 Arizona, which helps connect people to cooling centers, are also expected to lose funding in early next year.
"I'd probably be dead [without heat relief efforts], honestly," Nelson told KJZZ. "Honestly, I'd probably be dead because of the heat. And I know it's killing a lot of people out there."
Where can I learn more?
Extreme heat is driving deaths, illness, and policy responses well beyond Maricopa County. These stories look at income-based heat risk, Southwest death trends, Nevada protections, and rising American medical costs.
• In Spain, people in below-average income brackets face a higher risk of dying in heat waves.
• Across the Southwest, temperature-linked death tolls rose as another long, punishing heat season dragged on.
• In Nevada, lawmakers protected basic necessities that save lives during extreme heat waves.
• Nationwide, 237,000 people going to the ER each year reflects a widening heat crisis.
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