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Posted on: October 5, 2022

Maricopa County Public Health Releases Final Annual Heat Report for 2021

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PHOENIX (October 5, 2022) – According to the 2021 Maricopa County Department of Public Health (MCDPH) heat associated death report, 339 were recorded in 2021, the highest number of deaths that can be attributed to heat in the county since recording began in 2006.

"This tragic number of deaths shows us that heat continues to be a major issue affecting the health of Maricopa County residents,” said Dr. Nick Staab, medical epidemiologist at MCDPH. “Looking deeper at the numbers, we see that anyone can be at risk of serious illness and death from heat, and everyone needs to take precautions during the entire heat season.”

Key Points in the Report

  • Outdoor deaths: 
    • 75% of heat-associated deaths occurred outside. 
    • 130 deaths occurred among people experiencing homelessness. 
  • Indoor deaths:
    • One in four heat-associated deaths occurred indoors. 
    • 86% of people who died indoors had an air conditioner present. 
    • In 75% of cases with an air conditioner present, their air conditioner was not functioning; it was not turned on in 19% of cases; and 3% did not have working electricity.
  • Other key points:
    • Most heat associated deaths occurred in the months of June, July, and August, but heat-associated deaths can occur as early as April and as late as November. 
    • Three out of four heat-associated deaths occurred on days that did not have an excessive heat warning. 
    • 86% of heat-associated deaths were residents of Maricopa County, and two-thirds of those had resided in the county for over 20 years.

“These data tell us that it’s not just visitors or newer residents who can be severely affected by our hot weather,” added Dr. Staab. “Even when we think we’ve gotten used to Arizona summers, we need to take precautions like staying hydrated and avoiding outdoor activity in the hottest part of the day.”

It is also important to regularly check on loved ones, friends, and neighbors, especially those with chronic medical conditions, to prevent heat related tragedies. Water distribution and emergency cooling centers have been established throughout the county for those who do not have access to cool, indoor environments. A map showing all the cooling centers can be found at

It is critical to protect yourself and those around you from heat-associated illness, like heat stroke or heat exhaustion, and death by taking the following precautions every day during the heat season: 

  • Drink water throughout the day to prevent dehydration 
  • Don’t rely on fans as your primary source of cooling, especially once the temperature reaches 90 degrees or higher.
  • Come indoors frequently to an air-conditioned location to cool your core body temperature. If you do not have access to a cool indoor environment, you can find an Emergency Cooling Center near you at
  • Wear a wide-brimmed hat, sunscreen, and lightweight clothes when outdoors.
  • Never leave kids, older adults, pets, and others who may rely on you inside of a parked car.
  • Check on friends and neighbors, especially the elderly, to ensure sufficient cooling and supplies.
  • Seek medical care immediately if you have, or someone you know has, symptoms of heat-associated illness like muscle cramps, headaches, vomiting, confusion, no longer sweating, and rapid heart rate.

A person is included in MCDPH’s heat-associated death data only after the Maricopa County Medical Examiner confirms that heat has caused or contributed to the cause of death on a decedent's death certificate. Prior to confirmation, potential cases are listed on Public Health’s website as “under investigation.”

All heat-associated deaths are preventable, and MCDPH will continue to work with partners to end the tragedy of heat-related deaths in Maricopa County.

For more information on emergency cooling centers, heat death statistics, and to sign up for heat warning alerts, go to

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