CHICAGO — It's now official — this is the second coldest day in Chicago weather history.
Weather records here go back 148 years to 1870. Wednesday's high of 10 below zero at midnight, and this morning's minimum of 23 below zero averages out to minus 17 degrees. The only other day colder was Christmas Eve Day, 1983 when the high and low were minus 25 and minus 11 degrees respectively, averaging 18 below zero.
A little perspective on how rare this is. There are 54,020 official temp readings on file for Chicago in the 148 years since 1870, and Wednesday's minus 23 at O’Hare is only the 17th temperature which has dipped under 20 below zero!
New record low temperatures have also been set for January 30, including 22 below zero at O’Hare (old record minus 15) and 24 below zero at Rockford (old record minus 19). In Rockford the midnight reading was also 16 below zero, and assuming that will be their highest temperature today, it will establish a new all-time record for lowest high temperature for that location (old record was -14).
To say it's brutal out there is an understatement. Lake Michigan took on the appearance of a boiling cauldron as air of minus 20 degrees and colder made contact with water sitting just above the freezing level. I’ve lived here 40 years and never until today have never seen a more spectacular display of “sea smoke.”
Temperatures at 8 a.m. of minus 23 at O'Hare smashed a 53-year-old record set back in 1966. This morning's minimum of 24 below zero was the coldest in Chicago in the 36 years since the morning of January 20, 1985, when Chicago's all-time record low of minus 27 was recorded.
The bitter air has encouraged buildings to pop and creak, and delivered a host of other optical phenomena, like "sun dogs" caused by tiny suspended ice crystals in the brutally cold air.
The barbaric cold isn't done with us. Air temps won't reach zero until Thursday afternoon, and highs today may not rise above 13 below zero in many areas, and lows tonight will bottom out at 26 below zero, within a degree of Chicago's all-time record low of minus 27 set on January 20, 1985. Winds chills will rise only to minus 35 to 43 below zero this afternoon, and fall back to 40 to 45 below zero tonight.