Over the weekend, most areas of the state saw their first taste of 32 degrees or colder. Here are the maps from the Midwestern Regional Climate Center showing that the almost the entire state was covered. A few places in the Chicago area may have escaped thanks to the so-called Urban Heat Island (UHI) – lots of warm surfaces like roads, asphalt parking lots, roofs, and waste heat from buildings. For example, O’Hare AP reached 33 degrees. Meanwhile, Mt. Carroll in northwest Illinois reported 20 degrees on October 18. Now that’s cold.
