Confirmed heat deaths in Maricopa County keep rising even as weather grows milder

The number of confirmed heat deaths over the summer in America’s hottest metro has continued to rise even as the record-setting high temperatures that blasted Phoenix over the summer give way to relatively milder weather with autumn’s approach.

Public health officials in Maricopa County, Arizona’s most populous county and home to Phoenix, said this week that 202 heat-associated deaths had been confirmed for 2023 as of Sept. 9; far more than the 175 confirmed by the same time last year.

Another 356 deaths this year are being investigated for heat causes.

Forensic pathologists say that it can often take weeks, even months of investigation that can include toxicological tests to determine whether heat was a contributing factor in someone’s death. For example, at the end of 2022 the county had confirmed 378 heat-associated deaths, but that number later grew to 425 as investigations played out.

The confirmed heat deaths this year included 51 that occurred indoors, most of them because an air conditioner was not working or turned off. People without permanent homes accounted for 42% of the annual heat deaths confirmed so far.

Phoenix was continuing to hit heat records as recently as last weekend, as it marked the 55th day this year that the official reading at Phoenix Sky Harbor Airport reached at least 110 degrees Fahrenheit (43.3 degrees Celsius).

Phoenix experienced the hottest three months since record-keeping began in 1895, including the hottest July and the second-hottest August. The daily average temperature of 97 F (36.1 C) in June, July and August passed the previous record of 96.7 F (35.9 C) set three years ago.


PHOENIX, ARIZONA - JULY 15: A person walks down the street with an umbrella during a heat wave on July 15, 2023 in Phoenix, Arizona. (Photo by Brandon Bell/Getty Images)

After several days this week with typical monsoon season weather that included some precipitation, Phoenix on Thursday expected relatively milder weather.

At least milder for those who live in and around Phoenix.

"A very nice mid September day is expected across the region with mostly sunny skies and high temperatures in the upper 90s to around 100 degrees," the National Weather Service’s Phoenix office said on social media.