At the moment, I'm experiencing the weather of Chicago's future. I'm sitting outside at a St. Louis Bread Co. (aka Panera) in St. Louis while Anne does a 10 km (6 mi) run at Forest Park. The temperature has risen 2.8°C (5°F) in the past hour and promises to rise another 5°C (9°F) in the next two. It should hit 32°C (90°F) today, as it does most days in the summer down here, with the possibility of cooling down to 27°C (80°F) by bedtime.
St. Louis is warmer than Chicago, and will probably always be. But the weather people find normal in St. Louis (mild winters, hot summers) is becoming normal in Chicago. By 2050, St. Louis may have frost-free winters, and Chicago may have double or triple its current number of 32°C (90°F) days every summer.
At least Chicago has the lake, which helps.