Temperatures Sunday night are falling quickly under a mostly clear sky, light wind and freshly fallen snow. Many locations have dropped into the low single digits, with sub-zero readings across NW Illinois and just west of the Mississippi River.
High pressure settling in over northern Illinois and southern Wisconsin will keep winds fairly light through the night, but help push temperatures down below zero by Monday morning. The forecast low for Rockford is -5 degrees. While the winds should remain light for much of the night, even the slightest breeze will help push wind chills down to around -10 degrees, to -15 degrees, by morning. Make sure you layer up, especially in the morning, as most head back to work and school. Southwest winds will increase slightly during the day, bringing temperatures into the low 20s Monday afternoon. Wind chills during the day will remain in the upper single digits and low teens.