If your apartment turns into an oven every July and the AC is a luxury you ration, the city just put a number on what that does to people. It is 21.
That is how many New Yorkers died of heat stress in 2025, according to the Health Department’s annual Heat-Related Mortality Report. The year before, the same report counted three. The decade average is about seven. Last year was seven times worse than the one before it, and triple the normal.
Of the people who died, all but three were Black or Latino. Officials tied that directly to systemic racism and historical inequities. And most of the victims did not die in the street. They died at home, in their own apartments, without air conditioning.
The spike came from one stretch of weather: a record-breaking heat wave in June 2025 that lasted four days and killed 19 people. The heat hit housing that was never built to cool down and people who cannot afford to run a unit even if they own one.
And that 21 is only the deaths heat caused directly, the heat stroke and hyperthermia. The city estimates that another 500 New Yorkers, on average, die every year from chronic conditions that hot weather pushes over the edge, the heart and lung problems that a brutal week of humidity quietly finishes off. Climate change is making those weeks more common and more intense.
The report flags neighborhoods in eastern Brooklyn among the most vulnerable in the city, the same low-income, heavily Black and Latino areas that show up at the wrong end of almost every map like this one.
The city’s own climate officer was blunt about where the fix lives. “Most heat-related deaths occur at home, making access to safe and affordable indoor cooling one of the most effective ways to protect New Yorkers,” Chief Climate Officer Louise Yeung said in the statement announcing the data. In plain terms: people are dying indoors because they cannot keep their own homes cool, and the answer is getting them air conditioning and the money to run it, not just telling them to hydrate.
If a heat wave is coming and your place is unsafe, the city opens free cooling centers across the five boroughs during heat emergencies. If you know an older or homebound neighbor without AC, check on them during a heat wave. Last year 21 people died from heat stress.
Featured image: Ed Reed/Mayoral Photography Office
