Maricopa County says heat-related deaths fell again in 2025, to 430.
Why it matters: The decline suggests public-health operations can move the mortality curve even in extreme desert heat. That matters for cities, employers and health systems across the U.S. Southwest as heat becomes a bigger planning risk.
- Maricopa County recorded 430 heat-related deaths in 2025, down from 608 in 2024 and 645 in 2023.
- County officials said 2025 marked the second straight year-over-year decline in heat-related deaths.
- The county's public-health report said heat-related deaths occurred every day from June 13 to Sept. 5, a stretch of 85 days.
- The county has expanded a heat-relief network, surveillance and public dashboards; the 2026 network launched May 1.
Maricopa County, Arizona, home to Phoenix and some of the most extreme heat in the U.S., is showing a rare bit of progress. County officials say heat-related deaths fell to 430 in 2025, the second consecutive annual decline after 608 in 2024 and 645 in 2023. The county's annual heat report says deaths still happened every day for 85 straight days, from June 13 through Sept. 5.
Public-health officials say the county's response has centered on a countywide heat-relief network, expanded surveillance and better public-facing dashboards. Dr. Nick Staab, chief medical officer for the Maricopa County Department of Public Health, said, "We are excited to see this continued trend of decreasing heat related deaths in our community." He added that he is hopeful expanded access to heat-relief sites and more information about the risks of heat illness and death is "percolating into our community." County officials outlined the 2026 heat plan in May.
The county's 2026 Heat Relief Network launched May 1 with cooling, hydration and respite sites across the Valley. A CDC review of Maricopa County's cooling-center effort found the number of centers doubled from 56 in 2020 to 112 in 2023. It also found the county added longer hours, weekend access, street signage and a bilingual heat-relief call center. The CDC's report said street signage was viewed as the best way to advertise cooling centers by 56% of cooling-center visitors and 69% of the general public surveyed.
The county says the problem remains severe. In 2025, people experiencing homelessness accounted for 49% of heat-related deaths, 74% occurred outdoors and Phoenix had the largest share of injury locations with 233 deaths. County officials said each death is a preventable tragedy and pledged to keep working with community partners to reduce the toll further.
By the numbers
- 430 - Heat-related deaths in Maricopa County in 2025, down from 608 in 2024 and 645 in 2023
- 85 - Consecutive days in 2025 when heat-related deaths occurred, from June 13 to Sept. 5
- 112 - Cooling centers in Maricopa County in 2023, up from 56 in 2020
Yes, but: The county's decline is encouraging, but the sources do not prove which interventions drove it most. Heat deaths also remained high in 2025, and summer 2026 totals were still unfolding.
What's next: Maricopa County's 2026 heat season was still in progress when the reporting was compiled, so the final death toll for this summer was not yet known.