“Dangerously hot and humid” conditions are moving into the Chicago area this weekend, potentially pushing the heat index as high as 105 degrees, according to the National Weather Service.
Temperatures are expected to reach as high as 95 degrees on Saturday and continue climbing throughout the weekend and into Monday, the weather service said. An extreme heat warning will remain in effect in Cook County from 10 a.m. Saturday to midnight Monday.
The heat index, a tool that that factors humidity into the air temperature, will remain over 100 degrees throughout much of the weekend, according to the weather service. Temperatures in the city won’t drop below 75 degrees, and some areas more impacted by the urban heat effect, such as areas with less tree coverage, could see them stay as high as 80 overnight.
“First and foremost I want to make sure every Chicagoan understands the danger of this moment and anytime we have extreme heat,” Mayor Brandon Johnson said at a press conference Friday morning.
Brett Borchardt, a meteorologist with the National Weather Service, said the first heat wave of the year could extend into Tuesday. He warned that the duration of the heat wave, with high overnight temperatures and the amount of time since the last heat wave could make this one deadlier as people are less prepared.
“Heat impacts are cumulative,” Borchardt said. “If you go through one day of heat, you’re OK, but when you get to days three and four, that’s when it really starts to impact our bodies, especially when we can’t cool off at night.”
Since about 11% of the city doesn’t have access to air conditioning, Chicago Department of Public Health commissioner Dr. Olusimbo Ige urged those without a way to stay out of the heat to visit cooling centers, or at the very least “cool their collars” by using cold rags to lower the temperature of key areas on the body, such as the neck, wrists, groin and armpits. She also suggested those who don’t have air conditioning to open windows at least slightly to allow for airflow.
Signs of an emergency include confusion, headaches and vomiting, Ige said, who urged those with symptoms to call 911.
“Fans [alone] do not work,” Ige said. “If indoors means no air conditioning, then a cooling location may be a safer choice.”
(2/2) High temperatures in the 90s with high humidity will lead to heat indices rising above 100° for multiple consecutive days. Ensure that you’re staying cool and hydrated! pic.twitter.com/eH7dE54Me0
— NWS Chicago (@NWSChicago) June 20, 2025
Over the last five years, the city has seen 485 heat deaths, with those at the highest risk of being harmed by the heat being men, the elderly and those who already have other illnesses, according to Ige. Overall, heat deaths and emergencies are on the decline.
The American Red Cross urged everyone to stay cool and hydrated and to check on others during the heat wave. Pet owners also are urged to closely watch their pets, especially on walks.
Anyone in the city can call 311 to request a welfare check or get in touch with city services like cooling centers. A city robocall system will also be doing outreach to seniors through the weekend, in addition to Department of Family and Support Services teams checking in on homeless encampments to encourage transport to cooling centers.
“Knowing what to do to protect yourself and loved ones from extreme heat can save lives,” Red Cross division disaster director Tony Lasher said in a statement. “We’re asking everyone to check on friends and neighbors, especially older adults, people with chronic conditions, outdoor workers and athletes.”
The following cooling centers will be open Saturday through Tuesday:
- The Chicago Department of Family and Support Services will have six community service locations open from 9 a.m. to 5 p.m.;
- Garfield Center will be open for cooling on Saturday and Sunday from 9 a.m. to 5 p.m., with case management services until 4 p.m.; and
- Chicago Park District, Chicago Public Library, City Colleges of Chicago and Chicago Police Department locations will be open for cooling during regular hours of operation.
- When temperatures are above 90 degrees, the city’s 21 senior centers 8:30 a.m. to 4:30 p.m.; the center at 78 E. Washington St. is open 10 a.m. to 5 p.m.
The city’s outdoor pools will also open Saturday, which are open seven days a week.
City officials suggested those with air conditioning to keep them set between 75 and 78 degrees to lower the burden on the electrical grid. ComEd has increased staffing levels and recent improvements are expected to prevent failures under the stress of high usage.
“We expect energy demand will increase significantly with the heat, however, our system is prepared,” said Valerie Coletti, a Com Ed official, at the press conference Friday morning.
Some areas of the city stand to be hit harder by the heat. In a study of heat deaths and other high-temperature related emergencies released this month, city officials said the zip codes 60620, 60623, 60628 and 60651 saw the most calls for service during heat advisories in 2023 and in years since.
Some of the areas listed are the same areas that saw the highest number of deaths during the 1995 heat wave that killed 739 people across the city, such as Englewood and other majority Black neighborhoods. Largely Latino neighborhoods like Humboldt Park and parts of Austin have seen more heat emergencies in recent years.
“There are regional variations in how people experience heat,” Ige said.
Numerous studies have blamed the deaths of so many elderly in South and West Side Zip codes nearly 30 years ago on the city’s failure to address poverty and disinvestment in those neighborhoods.
“It challenges the city to recognize the damage of extreme heat so that we never see tragedy like that again,” Johnson said.
