If you planning to travel to Six Flags Great America, Gurnee, Illinois, here is your 6-day travel weather forecast to make sure you have all the essentials needed during your stay. Start your day when the sunrises at 12:59 PM. The temperature feels like 21.4 with a humidity level of 68 so dress accordingly. Cloud coverage is 49 percent with visibility at 15 percent. Today’s UV index is 1, don’t forget the sunscreen if you need it! Today’s winds are traveling south-southwest at a speed of 9 MPH. At the end of the day don’t miss the sunset at 10:20 PM.