1995 Chicago heat wave

[2] The heat wave also heavily impacted the wider Midwestern region, with additional deaths in both St. Louis, Missouri[3] and Milwaukee, Wisconsin.

[7] North of the border, Toronto, Ontario reached 37 °C (99 °F), when coupled with record high humidity from the same airmass resulted in its highest ever humidex value of 50 C (122 F).

[citation needed] The heat wave was caused by a large high pressure system that traversed across the midwest United States.

This is also called a harvesting effect, in which part of the expected (future) mortality shifts forward a few weeks to the period of the heat wave.

Initially some public officials suggested that the high death toll during the weeks of the heat wave was due to mortality displacement; an analysis of the data later found that mortality displacement during the heat wave was limited to about 26% of the estimated 692 excess deaths in the period between June 21 and August 10, 1995.

At Northwestern University just north of Chicago, summer school students lived in dormitories without air conditioning.

[2] From the moment the local medical examiner began to report heat-related mortality figures, political leaders, journalists, and in turn the Chicago public have actively denied the disaster's significance.

Although so many city residents died that the coroner had to call in seven refrigerated trucks to store the bodies, skepticism about the trauma continues today.

"[9] The American Journal of Public Health established that the medical examiner's numbers actually undercounted the mortality by about 250 since hundreds of bodies were buried before they could be autopsied.

[16] In 2018, filmmaker Judith Hefland created Cooked: Survival by Zip Code, a documentary exploring the unequal death rates observed during the 1995 heat wave.

Cooked examines the factors that most directly contributed to these unequal death rates, and posits that such a crisis was not a one time catastrophe, but rather a dangerous trend occurring beyond Chicago.

Most directly, the lack of adequate warning and failure to utilize pre-existing cooling centers disadvantaged impoverished groups, and caused particularly devastating effects in Chicago's poorest areas.

Urban heat islands still exist throughout the United States and beyond, and impoverished, minority groups still disproportionately occupy these at-risk neighborhoods.

[20] A wet-bulb temperature of 95 °F (35 °C) may be fatal to healthy young humans if experienced over six hours or more for children one month of age as well as the elderly 70 and over.