The Sunday July 17, 2016 Humana Rock'n'Roll Chicago Half Marathon in Illinois is a mostly flat course winding through the city of Chicago. The forecast for this Sunday is a high of 88 with a chance of scattered thunderstorms, some possibly severe, so wear a hat or visor to protect your eyes, and bring your wind & rain jacket if you want to stay dry! The event is also listed at our Illinois Half Marathons page.