ASK TOM: Has Chicago's high and low temperature ever been the same?

Dear Tom,

On how many days in Chicago weather history have the day’s high and low temperatures been the same? That is, the temperature did not change at all?

– Doc. B, U.S. Navy


Dear Doc,

Since 1870, it has happened once. Chicago’s weather is always in a state of flux, and rarely do temperatures hover at exactly the same value for more than a few hours. That’s the reality we live with.

On very rare occasions, though, when the progression of weather systems across the Midwest has greatly slowed and Chicago finds itself with high humidity, a foggy and densely overcast sky, and practically no wind, the temperature can remain absolutely stationary. Such was the case for a record 30 consecutive hours from 9 p.m. Feb. 5, 1942, to 3 a.m. Feb. 7, when Chicago’s temperature sat unchanging at 35 degrees.