Record-shattering March heat wave may have led to as many as 28 deaths in the Valley

The Valley’s unprecedented March heat wave may have contributed to as many as 28 deaths.

So far in 2026, officials are investigating 42 possible heat-related deaths, according to data released Tuesday by the Maricopa County Department of Public Health. The majority of those cases are from March, when the Valley had a record-shattering nine days in triple-digit heat.

One heat-caused death has been confirmed so far this year. According to the Maricopa County Office of the Medical Examiner, an 80-year-old man with underlying health conditions died outside his home on March 20, when the high temperature reached 105 degrees — the hottest temperature ever recorded in March in Phoenix.

Another 27 possible heat deaths from March remain under investigation.

If confirmed, the dozens of possible heat-related fatalities would be unheard of for so early in the year — over the last six years, Maricopa County has reported only one other heat-related death in March, County data shows.

Maricopa County Department of Public Health medical director Dr. Nick Staab pointed out, in spite of the heat wave, temperatures this March still cooled off at night.

“What we like to always focus on is overnight lows as well — it’s kind of that sustained heat with high overnight lows that we see as the biggest risk,” Staab said.

He said the summer ahead will inevitably bring much more dangerous conditions.

“We definitely want to focus on the upcoming, known, long heat event that we have every year,” Staab said.

Maricopa County confirmed 430 heat-related deaths in 2025.

Staab said the first heat-related deaths in 2026 should be a reminder to everyone in the Valley to take the risk of extreme heat seriously.

“Those who have unstable housing or who may be using substances, we know they are at highest risk in our community, but everyone may find themselves in a situation where they don’t have a reliably cool place to go,” Staab said.

As summer approaches, Staab encourages Maricopa County residents to be aware of resources for keeping cool and to check in regularly with vulnerable family, friends and neighbors.