Temperatures fell early Wednesday to make it the coldest Jan. 30 in Chicago history.
By 2 a.m., the temperature at O'Hare Airport (Chicago's official recording station) was minus 16 degrees. That was enough to break the old daily record for Jan. 30, which was 15 degrees below zero, set on Jan. 30, 1966.
The temperature then continued to fall throughout the morning, reaching a new daily record low of minus 23 degrees.
The lowest temperature in all of Chicago history is 27 degrees below zero, a record set on Jan. 20, 1985. That record too remains in jeopardy, as overnight lows from Wednesday night into Thursday morning look to be between minus 22 degrees and minus 30 or 32 degrees west of the Fox Valley.
The overnight low at O'Hare looks to be around 26 degrees below zero, so close to the record - but even a one-degree shift could set a brand new low.
Those temperatures aren't even as cold as it truly feels in Chicago, as a Wind Chill Warning remained in effect across the area through 12 p.m. Thursday.
While morning lows were between 15 and 25 degrees below zero, wind chill values between minus 45 and minus 55. Afternoon highs were expected to reach minus 10 to minus 20, but feel more like 35 to 50 degrees below zero.
Winds gusting up to 35 mph during the day will ease overnight, though wind chill values will still be around minus 30 to minus 40 degrees — meaning a few more records could be broken Thursday, including the low for the day and the record low maximum.