The number of heat-related deaths in Maricopa County dropped 30% last year — the second year in a row of decreasing deaths, after a decade of increases.
The Maricopa County Department of Public Health has yet to release its final report on heat deaths in 2025. But at a Phoenix City Council meeting last week, Maricopa County chief medical officer, Dr. Nick Staab said the county saw 427 heat deaths in 2025, down from 608 the year before. One death from 2025 still remains under investigation.
“We are excited to see this continued trend of decreasing heat related deaths in our community,” Staab said.
The 608 deaths reported in 2024 were just a 6% decrease from the 645 deaths reported in 2023. So the 30% drop in deaths in 2025 was very significant, Staab said.
At the end of last year’s heat season, officials had expected to see a drop of about 20%.
Last summer was one of Phoenix’s hottest on record. Staab said policy changes are likely what drove the decrease.
“I’m hopeful that much of our effort in the last couple of summers expanding access to heat relief sites, as well as putting out more information about the risks of heat-related illness and death is percolating into our community,” Staab said.
Staab said officials are still analyzing the data to better understand which policy changes were most effective.
For the last two summers, the city of Phoenix has kept a heat relief site open 24-hours-a-day and has offered late-night hours at additional sites.
The city's extended-hour heat relief sites last summer served more than 5,600 individuals, according to Phoenix's Office of Homeless Solutions.
The city is planning to offer similar heat relief services again this summer. The council approved more than $5 million in federal pandemic relief funds, opioid settlement funds, and city funds to cover the costs of heat relief operations in 2026.
“We treat extreme heat as the public health emergency that it is,” Phoenix Mayor Kate Gallego said. “Even one heat death is still too many.”
Gallego called heat relief a valuable investment for the city, but noted these efforts will need more stable sources of funding to continue or expand in future years.
“I want to be clear, Phoenix cannot do this alone,” Gallego said. “More illnesses would be prevented and more lives saved with additional support from the state and federal government as well as other cities in the Valley.”
