Music festivals and the Mackinac race will happen amid temperatures soaring into the 90s.
Temperatures Friday night were still mild, with a crowd enjoying the band Plain White T's at the World's Largest Block Party downtown. It was one of several festivals going on around the city and pretty much all of them were gearing up for much hotter conditions Saturday.
The music at the Taste of River North was from the 1980s, but the temperature will be reaching into the 90s Saturday. Organizers encourage the crowds to stay hydrated with plenty of water and also try samplings of food from River North vendors.
"Our restaurant vendors - they sell water and soft drinks," said Larry Janus of Taste of River North. "We ask them - please make sure you're stocked up and it's cold."
At the Pitchfork Music Festival on the near West Side, organizers will have musicians from the 45 bands on three different stages make frequent announcements encouraging people to drink plenty of water.
"We'll drop pallets in the park if it really does get hot," said Chris Kaskie, president of the Pitchfork Music Festival. "We'll kind of drop them - not in a helicopter, obviously - but just put them throughout the park and then people can just grab them."
City officials say they plan to have cooling centers open and are encouraging neighbors to check on each other.
"We are asking Chicagoans to check on any older or frail neighbors," said John Pfeiffer of the Chicago Department of Family and Support Services.
The forecast calls for several days of extreme heat ahead which doctors say could make matters worse.
"If there's multiple days in a row of your body being exposed to that type of heat, it's harder for your body to recover, especially the elderly," said Dr. Teresa Davis of Rush University Medical Center.
"We've certainly had hot days before. Tonight is supposed to be pretty pleasant, I think tomorrow probably a little warmer, but we're all set to go," said Father Tom Hurley, pastor at Old St. Pat's Catholic Church.
Organizers have also brought in extra water to this year's World's Largest Block Party, and they have paramedics on standby. For Friday night's headline band, Plain White T's, the extreme temperatures can sometimes make for a more memorable concert experience.
"They are battling Mother Nature out there to see us play, so we are going to play that much harder and just make it that much more of an event," said Tom Higgenson of Plain White T's.
Saturday night's headliner at the World's Largest Block Party will be Canadian band Barenaked Ladies. The festival starts at 5 p.m.
Pitchfork Music Festival and the Taste of River North start during the day during the heat of the day around noon on Saturday.