Confirmed heat deaths in Arizona’s most populous metro keep rising even as the weather turns cooler

Confirmed heat-associated deaths in Arizona’s most populous county continue rising even as the weather turns cooler in the hottest metropolitan area in the U.S. This weekend’s forecast calls for high temperatures in the double digits.

Maricopa County public health data released this week shows that as of Sept. 23, there were 295 heat-associated deaths confirmed, with a similar number — 298 —- still under investigation for causes connected to the heat.

The rising numbers are keeping Maricopa on track to set an annual record for heat-associated deaths after a blistering summer, particularly in Phoenix. No other major metropolitan area in the United States has reported such high heat death figures or spends so much time tracking and studying them.

By this time last year, 40 fewer heat-associated deaths were confirmed and 109 fewer deaths were still under investigation.

Scientists predict the numbers will only continue to climb as climate change makes heat waves more frequent, intense and enduring,

Even as the full human cost of the sweltering summer becomes more evident, the weather in Phoenix is growing milder as fall begins.

The National Weather Service said the high temperature in Phoenix was expected to top 104 degrees Fahrenheit (40 Celsius) on Friday. That high was forecast to slide to 99 degrees Fahrenheit (37.2 Celsius) on Saturday and into the high 80s (around 31 Celsius) on Sunday and Monday

It can take months of investigation, including toxicological tests, to determine whether heat was a contributing factor in someone’s death. At the end of 2022, the county had confirmed 378 heat-associated deaths, but later, as investigations played out, that number grew to 425, the highest total ever recorded.

About three-quarters of Maricopa County’s confirmed heat deaths so far this year were outside, including at bus stops and in parks. About 44% of those who died were people experiencing homelessness in a county where an estimated 10,000 don’t have permanent housing. More than a third of those who died were 65 or older.

There have been 74 indoor heat deaths in the county confirmed so far, including 63 in homes where the air conditioning was not working or turned off.

Phoenix this summer 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 in July also set a record with a 31-day streak of highs at or above 110 F (43.3 C), creating a health hazard for people whose bodies were unable to cool off sufficiently amid such persistent, relenting heat.