The National Weather Service also issued a flash flood warning for the portions of the area.
It'll take several hours until the chance of bad weather moves completely out of the area, and Sunday looks like a beautiful day, with some clouds and temperatures in the mid-80s.
Chicago-area temperatures peaked in the low-to-mid 90s before the thunderstorms arrived to cool things off. Combined with higher humidity, the temperatures made being outside uncomfortable, with a heat index approaching 105.
Saturday's 90-degree temperatures made it the 39th day this year with temperatures that high; the record is 47, set in 1988, according to the National Weather Service. Saturday also was the 40th straight day with a high in the 80s or warmer, according to agency figures; that's the third longest ever behind 46 days in 2010 and 42 in 1955.
There's a good chance both of those records fall this summer – we've just entered August.
Dawn Rhodes, Heather Gillers, Kevin Williams, Rosemary R. Sobol and Jennifer Delgado contributed to this report.