Heat Index Could Hit 105 in Chicago as City Rushes AC Upgrades to 42 Park Fieldhouses

Chicago is heading into another stretch of dangerous heat this week, with the National Weather Service warning that Wednesday could feel as hot as 105 degrees even though the actual temperature will only reach the mid-90s.

The National Weather Service issued a hazardous weather outlook covering an excessive heat risk through Thursday. Tuesday is forecast to hit 91 degrees but feel closer to 100 in parts of the city. Wednesday is expected to be the worst day, with a high of 94 degrees and a heat index that could reach 105. Poor air quality is expected to linger through midnight Wednesday, and the weather service is telling people in sensitive groups to stay indoors. Thursday should cool slightly to a high near 89, though it may still feel like 100 with the humidity factored in. A lake breeze could offer some relief to people near the shoreline. Temperatures are expected to ease by the weekend, when thunderstorms are possible.

This round of heat won't be as bad as what hit Chicago at the end of June, when dew points climbed into the upper 70s and made the air feel as hot as 108 to 115 degrees over several days. NBC 5 Storm Team meteorologists say the difference this week comes down to moisture: dew points are expected to stay in the 60s rather than the 70s, which keeps the air sticky and muggy but not quite as oppressive. Still, heat index values are expected to run between 100 and 104 as the week goes on, with Tuesday and Wednesday the most dangerous days.

At least three people died on the South Side during extreme heat in early July, according to the Cook County medical examiner's office cited by the Chicago Tribune. That heat wave pushed heat indices past 100 degrees for multiple consecutive days and forced the city to open cooling centers across its network of parks and libraries.

The Chicago Park District and Mayor Brandon Johnson last week announced a $1 million push to add or upgrade air conditioning systems at 42 fieldhouses, concentrated in South and West Side neighborhoods that rank as the most vulnerable to extreme heat. Twenty of those parks are set to have improved air conditioning in place by the end of summer, another 10 by the end of the year, and the remaining 12 will get upgrades later as part of larger capital projects already planned for those sites.

The park list includes Armour Square Park in Armour Square, Clark Park in Austin, Cornell Square Park in Back of the Yards, Piotrowski Park in Little Village, Palmer Park in Roseland and Gage Park in the Gage Park neighborhood, among others spread across the South and West sides. Fieldhouses slated for future capital work include Douglass Park, Garfield Park, Marquette Park and Washington Park.

The city picked the sites using the Chicago Heat Vulnerability Index, a mapping tool built by Northwestern University that draws on historical temperature data, rates of heat-related illness and other neighborhood characteristics to identify where residents face the greatest risk during extreme heat. West Garfield Park, North Lawndale and Chicago Lawn came back as the most vulnerable neighborhoods in that analysis, and the index found that most of the South and West sides fall into either the "most vulnerable" or "vulnerable" categories.

"For too long, communities that have faced the greatest impacts of extreme heat have also borne the weight of underinvestment in the resources needed to keep neighbors safe," Johnson said in a statement announcing the funding. "By strengthening our neighborhood parks, we are ensuring that every resident, regardless of their ZIP code, has access to safe, welcoming spaces to cool off during dangerous heat events."

The Park District is also using the rollout to test what it calls cost-effective cooling technologies at some sites, with an eye toward applying whatever works well to future projects across the system. Many of the fieldhouses getting upgrades this year sit in neighborhoods, including Austin, Back of the Yards, Englewood and South Lawndale, that have some of the oldest park buildings in the city and have long lacked reliable air conditioning during summer months.

The park district's cooling center webpage lists current hours and locations for residents looking for air-conditioned space during this week's heat, along with information on public pools and beaches. The Park District is urging anyone without reliable air conditioning at home to use those facilities, particularly Tuesday and Wednesday when the heat index is expected to peak.

The 20 fieldhouses slated for upgrades by the end of summer have only a few weeks left before that deadline arrives.