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 ORD record →

Best month

September

81.3% on time · 397 flights

Worst month

July

57.2% on time · 419 flights

Month Flights On time Cancelled When late, by
January 326 72.8% 6.13% 81 min
February 329 71.3% 0% 89 min
March 446 64.3% 6.73% 129 min
April 512 71.8% 3.52% 90 min
May 497 73.9% 2.01% 73 min
June 413 69.3% 2.91% 102 min
July 419 57.2% 2.63% 104 min
August 413 73.9% 2.66% 117 min
September 397 81.3% 0.25% 74 min
October 478 72.7% 0.21% 65 min
November 427 69.1% 5.39% 83 min
December 367 65.9% 0.82% 86 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.