Dear Tom,

January is Chicago's coldest month, but is it always the coldest month every winter?

—James Proust

Dear James,

On average, January is Chicago's coldest month, but it's not necessarily the coldest month in any given winter. Long-term temperature averages at Midway Airport (1929-2011) rank January as the city's coldest month with 23.9 degrees followed by February at 27.9 degrees and December at 28.9. However, it's not often that the city's wildly variable weather adheres closely to those averages. More often than not, Chicago's month-to-month temperatures consist of large swings above and below the averages. In that vein, the data suggest it's premature to assume winter's coldest temperatures are behind us. February has been Chicago's coldest month in 18 of the past 83 winters, and March was the season's coldest in the winter of 1931-32.