CHICAGO — A study that had Chicagoans attach sensors to their cars during a summer day found significant disparities in heat across the city.
The Chicago Department of Public Health has released the results of Heat Watch 2023, which charted areas of the city most impacted by the extremes of climate change. Chicago was one of 18 cities participating in the national Heat Watch 2023 study.
One hundred volunteers drove 29 routes across 228 city square miles and collected almost 140,000 measurements from their car sensors on July 28, a day in which temperatures topped out at 99 degrees, according to the report.
The data showed a variance of up to 22 degrees between areas of the city. You can check the average heat level at your own address here.
Heat peaked predominantly on the South and West sides, where there is a density of residential buildings and a lack of “sufficient tree canopy cover to keep residents cool,” according to the report.
Other sweltering spots included industrial areas that retain heat throughout day and “radiate into surrounding areas as well,” according to the report.
Nature preserves and open-space areas provided cooling buffers. The full stretch of the lakefront also stayed cool compared to the rest of the city.
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On top of escalating heat waves, the city experiences the “urban heat island” effect, in which areas with heat-absorbing pavement and lack of trees and shade contribute to weather conditions.
The first-of-its-kind study provided a “new level of detail” on the effect, allowing city leaders to better pinpoint hot spots where the need for outreach and safety resources is greatest, according to the report.
The data will support the work of Northwestern University’s Defusing Disasters Global Working Group, which is developing a local heat vulnerability index.
“Heat Watch 2023 was just the beginning,” Raed Mansour, the health department’s director of Environmental Innovation, said in a statement. “While it is just a snapshot of data, this report helps shine a light on heat and its disproportionate impacts so we can look at ways to more equitably support Chicagoans.”
Chicago tied its all-time heat index and broke a daily temperature record during a particularly brutal stretch in August.
A Tribune investigation found vulnerable populations and communities on the South and West sides suffer most during heat waves. In 1995, a heat wave killed over 700 people in the city, with a majority of the victims being older people or those from disadvantaged communities.
In 2021, three elderly Black women died in their subsidized senior apartments in Rogers Park during a heat wave, a tragedy that sparked changes in housing policy in the city and state.
Here are some more heat maps for different parts of July 28:
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