With a cold Canadian-source high pressure overhead, clear skies and light north to northeast winds temperatures dropped into the upper 20s and lower 30s across much of  northeast Illinois and northwest Indiana early this Wednesday morning.. Frost Advisories and Freeze Warnings were in effect area-wide until 8AM. Lowest temps at area airport locations were 28-degrees at Waukegan, Lansing and Valparaiso, IN.

Just before sunrise, readings were leveling-off at many northern locations as an altocumulus cloud deck moved in from Wisconsin, cutting back on the radiational hat loss. In the Chicago “heat island” temps bottomed-out in the low to middle 30s. The official low at O’Hare was 33-degrees, just 4-degrees shy of the all-time record low for this date of 29-degrees set back in 1945.  

 Official temperature sensors at area airport locations are positioned about 5 feet above the ground, and actual temps at ground level can be a few degrees colder. So it’s safe to say 32-degree readings were likely even in the city at plant level.

Following is a list of low temperatures recorded at area airport locations this morning:

Location/Low Temp
Waukegan….28
Lansing….28
Rochelle….29
Sterling/Rock Falls….29
DuPage/West Chicago….30
Aurora/Sugar Grove….30
DeKalb….30
Freeport….30
Joliet….30
Rockford….31
Pontiac….31
Schaumburg….32
Kankakee….32
Wheeling/Palwaukee….33
O’Hare….33
Peru/Ottawa….33
Midway….36

NW Indiana
Valparaiso….28
Rensselaer….30
Gary….36

SE Wisconsin
Kenosha….29
Burlington/Lake Geneva….31
Janesville….32