Those going to the lakefront are being asked to take extra precautions.
On Tuesday, a teenager drowned while swimming and a child is in the hospital after being injured while playing in the lake.
Chicago and Cook County officials issued warnings on Wednesday asking people to be aware, take precautions, and help others.
You may tolerate the summer heat - or, perhaps, even enjoy it - but Chicago officials emphasized on Wednesday that someone you know may need help.
"There are vulnerable people and that tends to be the disabled and seniors, but if anyone feels they are getting sick they can all call us," said Commissioner Mary Ellen Caron, Chicago Dept. of Family & Support Services.
Chicago's Cooling Center at 10 S. Kedzie is open. If Chicago residents need a ride there or any help, they can call 311.
"You can't beat the heat, but they have an air conditioner on in here so that cools us off some," said Earline Wiliams, Homeless Citizen.
While some head indoors, others head out to the lakefront.
On the South Side, 16-year-old Shaun King apparently drowned Tuesday afternoon near 50th and Lake Shore Drive. He was a ward of the state and state official say he ran away from a youth home last month.
On Wednesday, that home, Lawrence Hall released a statement, saying, in part: "The death of the youth, who was a former resident in our program, is a tragedy. We remain focused on providing counseling and support to the youth and employees who knew him."
Also Tuesday, a 3-year-old girl apparently choked on food when she was hit by a wave. Witnesses pulled her from the water.
"It was a very sad, indescribable scene with the little girl. She was apparently trying to gasp for air," said Leticia Gallardo, witness.
Chicago park officials say children should swim with an adult and, if necessary, they can use a US Coast Guard approved life vest.
Lifeguards say other flotation devices are not allowed, like arm floaties, because they can deflate and provide a false sense of security.