Parts of Chicagoland will be dealing with bitter cold weather this morning. The National Weather Service says very cold temps are expected, with wind chills dropping to 20 to 25 below zero. A wind chill advisory is in effect until 9 a.m. for McHenry, Kane, and Dekalb counties. The cold conditions could cause frostbite on exposed skin in as few as 30 minutes. A Wind Chill Advisory in effect from 8 p.m. this evening to noon on Wednesday.