739 Dead in Five Days: Inside The Deadly Chicago Heat Wave of 1995
For five days in July 1995, Chicago experienced one of the deadliest weather disasters in American history — not a hurricane, not a tornado, but a slow, suffocating heat wave that killed 739 people.
The Numbers Behind the Heat
The crisis peaked between July 12 and July 16, 1995, when a massive high-pressure system parked itself over the Midwest and refused to move. On July 13, the temperature at Chicago Midway International Airport hit 106°F — the second-hottest reading ever recorded there, behind only the 110°F set in 1934. What made this heat wave especially dangerous wasn't just the daytime highs. Overnight lows stayed in the upper 70s and low 80s, giving the city's residents no relief and no chance to cool down before the next scorching day began.
Humidity turned dangerous heat into lethal heat. Unlike the dry heat waves of the 1930s, 1950s, and 1970s, this one carried moisture pulled north from Iowa. Dew points across the region climbed past 80°F, with one station in Appleton, Wisconsin recording a heat index of 153°F, a probable record for the Western Hemisphere. Across Iowa and southern Wisconsin, heat indices topped 130°F on multiple days. Wet-bulb temperatures in the Chicago area reached 85°F, edging toward levels that can overwhelm the human body's ability to cool itself through sweat.
Chicago's daily highs and lows that week tell the story:
Why It Turned Deadly
Chicago's urban heat island effect made things worse, pushing nighttime temperatures up by more than 2°F above surrounding rural areas as pavement and buildings radiated stored heat after dark. A temperature inversion trapped hot, humid, stagnant air at ground level, with almost no wind to stir it. Indoor temperatures in un-air-conditioned homes climbed above 90°F even at night.
The city's emergency response was slow. Officials didn't issue a heat emergency warning until the final day of the crisis, and the five cooling centers Chicago had set up went largely unused. Hospitals were overwhelmed — admissions rose 11% above average that week, and 35% among patients 65 and older, mostly for dehydration, heat stroke, and heat exhaustion.
Who Died, and Why
The victims were overwhelmingly elderly and poor. Many lacked air conditioning; others had it but couldn't afford to run it. Fear of crime kept many from opening windows or doors at night, a stark contrast to the heat waves of the 1930s, when residents slept outside in parks or along Lake Michigan. Sociologist Eric Klinenberg, author of Heat Wave: A Social Autopsy of Disaster in Chicago, later showed that the map of heat deaths closely mirrored the map of poverty in the city.
The toll fell hardest on Black residents, who died at significantly higher rates than white residents even after accounting for poverty — a disparity researchers have since studied as a case study in environmental racism. Hispanic residents, by contrast, had unusually low death rates, attributed to denser housing and stronger neighborhood social ties. Elderly women, generally more socially engaged than elderly men, also proved less vulnerable.
By August, 41 unclaimed bodies were buried in a mass grave in Homewood, Illinois. The scale of death was so great that the Cook County medical examiner had to bring in seven refrigerated trucks to store bodies. The death toll itself was a subject of dispute: the city's initial official count was far lower, and epidemiologists later revised the figure upward to the widely cited 739, arguing that many heat-related deaths had gone uncounted because victims were buried before autopsies could confirm heat as the cause.
The Legacy
The disaster sparked lasting debate over whether the death toll was exaggerated or a "media event," even as public health researchers defended and later revised the numbers upward. It also reshaped how cities plan for extreme heat, prompting research into early warning systems, cooling center utilization, and outreach to isolated elderly residents. The 2018 documentary Cooked: Survival by Zip Code revisited the disaster, arguing that the same conditions — heat islands, poverty, and unequal access to relief — persist in cities across the country today.
Years later, the 1995 Chicago heat wave remains a grim benchmark for how heat, more than any other weather event, kills quietly and disproportionately along lines of age and poverty.
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