At 7:08 this morning the temperature dropped to zero at Chicago’s official O’Hare observing site and held there for nearly a half-hour. That made the temperature fall exactly 63 degrees since the January 29 daily record high of 63-degrees was set this past Tuesday. That 63-degree pullback was the greatest 4-day January temperature fall-back back in Chicago records dating back to 1871. The old record was 61-degrees set back in January 1989. Most readings around the Chicago area were just above or just below the zero-degree mark – lowest readings of 3 or 4-below zero appeared to be in the Rockford area.
Wind chills were pretty consistent across northeast Illinois – most of the coldest observations falling -15 to -20 range. O’Hare bottomed out at -17 and Midway at -16. Coldest wind chills were a -22 at DeKalb and -21 at Rockford.