II. Phoenix, March 2026
At 2:57 p.m. on March 18, the temperature at Phoenix Sky Harbor reached 100°F. The National Weather Service confirmed it within the hour: the earliest triple-digit reading in the city's recorded history, forty-five days ahead of the typical first hundred-degree day. The previous earliest was March 26, 1988.
Then March 20. The equinox. The last day that technically belongs to winter. Phoenix hit 105°F, the hottest March temperature ever recorded in the city by five degrees. The average first 105-degree day normally falls on May 22, two full months away. At 105, concrete holds heat long after the sun shifts. Shade offers little. The air sits heavy against skin, and the body's own cooling fails before the person wearing it understands what's happening. Sweat evaporates before it can work. Core temperature rises.
An 80-year-old man with underlying health conditions died outside his home that day. Outside his home. At the threshold of the place where he lived, on a day the calendar still called winter.
The streak ran eight days. March 18 through 25, triple digits every afternoon. Nine days in the month reached 100 or higher. Before 2026, Phoenix had touched 100 in March exactly once, that single afternoon in 1988. The month's average temperature came in 12.5 degrees above normal. The National Weather Service issued an extreme heat warning for central and southern Arizona from March 19 through 22, the first ever issued in Arizona during winter.
Over the previous six years, Maricopa County recorded exactly one heat-related death in March. In March 2026, as many as 28 people may have died from heat.
Maricopa County's Heat Relief Network, the system of cooling centers and hydration stations for people without reliable access to air conditioning, was scheduled to open May 1. Through all of March, those doors stayed shut. The system designed to keep people alive in heat had yet to exist for the season. On schedule. The heat had outrun every measure the system had.
The medical examiner confirmed one death. Twenty-seven additional suspected heat fatalities remained under investigation.
Three days after the man died and five weeks before the cooling centers would open, the county published its 2026 heat plan:
"While the Heat Relief Network will not be operational until May 1, residents can stay cool in public indoor spaces such as libraries, malls, and community centers, which are available year-round."
When the county confirmed the first death on April 10, the announcement noted that Phoenix was "recovering from an unprecedented heat wave reported last month that resulted in the Valley experiencing high temperatures normally not seen until May or June."
On May 5, the county launched its heat surveillance dashboard. The season was already two months old.