30 Day Long Range Weather for Chicago Illinois Weather The weather for Chicago Heights are unpredictable sometimes. Weather conditions can range between hazardous heatwaves in the summer to bitterly cold winters that include significant snowfall. It is constantly important being ready for a variety of weather conditions within Chicago Heights. Stay updated about the weather forecast to plan your daily routines appropriately and attire appropriately. Keep secure and make the most of the diverse meteorological experiences that Chicago Heights has to offer.