Metro Phoenix has confirmed 18 heat deaths in 2023

As of July 15, at least 18 people had died of heat-associated causes in metro Phoenix, and another 69 suspected heat deaths are under investigation, according to the Maricopa County Department of Public Health.

State of play: Phoenix is in the midst of a historically long heat wave with no end in sight.

• Wednesday, the Valley recorded an overnight low of 97° — an all-time high, per National Weather Service.
• Those overnight lows can be particularly dangerous, especially among unhoused and elderly people, because the human body doesn't have time to recover from the extreme daytime temperatures, NWS meteorologist Tom Frieders told Axios Phoenix.

Flashback: This year's death count is lower than it was at the same time last year, when the medical examiner confirmed 29 deaths.

• Yes, but: We had a relatively mild June this year and the current heat wave is still ramping up, Phoenix chief heat officer David Hondula told us.

Zoom in: The first heat-related death confirmed this year was that of a 42-year-old unhoused woman whose body was found April 11 in a desert area in Glendale, according to the Maricopa County Office of the Medical Examiner. Temperatures were only in the mid-90s then.

By the numbers: Of the 18 confirmed heat-associated deaths, more than half were of people ages 65 and older.

• Six were people experiencing homelessness.
• Four of the deaths occurred indoors, but air conditioning was either not in use or not functioning.

Editor's note: This story has been corrected to state that six (not 12) people who were experiencing homelessness died of heat-associated causes this year so far.