Best time to fly Nashville to Chicago

Every month pooled across the years on record, so "July" means July generally rather than one particular July. Full BNA to MDW record →

Best month

January

90.2% on time · 131 flights

Worst month

June

54.9% on time · 157 flights

Month Flights On time Cancelled When late, by
January 131 90.2% 6.11% 38 min
February 120 83.2% 0.83% 49 min
March 164 79.2% 2.44% 73 min
April 166 75.3% 1.81% 42 min
May 171 60.6% 0% 46 min
June 157 54.9% 1.27% 52 min
July 175 73.3% 1.71% 55 min
August 168 76.2% 1.19% 66 min
September 159 89.9% 0% 28 min
October 170 78.8% 0% 51 min
November 160 81.2% 2.5% 57 min
December 152 80.8% 0% 42 min

What a seasonal pattern can and cannot tell you

Months differ for reasons that repeat — summer thunderstorms in the American interior, winter fog and de-icing in northern Europe, school holidays filling every seat and leaving no slack in the schedule. Those are real and they come back each year.

What the pattern cannot do is forecast a particular flight. A quiet month has late days and a bad month has punctual ones. Treat this as a way to choose between two dates you are indifferent about, not as a promise.