After a winter system brought more snow, ice and freezing rain to much of the Chicago area this week, dangerously cold temperatures are putting several counties under a Wind Chill Watch.
The watch was issued for McHenry, Lake, DeKalb, Kane, LaSalle and Kendall counties beginning Thursday evening and continuing through Friday morning.
It warns that wind chills as low as 30 below-zero are possible.
"A Wind Chill Watch means there is potential for a combination of very cold air and the wind to create dangerously low wind chill values," the National Weather Service warned.
The cold wind chills could cause frostbite on exposed skin in as little as 30 minutes, NWS said.
A Wind Chill Advisory is also in effect beginning at 6 p.m. Thursday for DuPage, Cook, Grundy, Will and Kankakee counties in Illinois and Lake, Porter, Newton and Jasper counties in Indiana, warning of wind chill values as low as -25. Teh advisory continues through noon Friday.
Highs Thursday will sit in the upper-teens and low-20s, but wind gusts of up to 25 mph will make for single digital wind chill readings.
Friday is set to be the coldest day so far this winter. Wind chill readings will sit between -15 and -25 during the morning hours. Temperature highs will only rise into the single digits for the afternoon, but wind chill readings will remain well-below zero.