Best time to fly Chicago to Nashville

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

Best month

September

79.8% on time · 397 flights

Worst month

July

56.3% on time · 419 flights

Month Flights On time Cancelled When late, by
January 326 67.5% 5.52% 81 min
February 329 72.3% 0% 67 min
March 447 61% 6.49% 85 min
April 512 74.3% 3.32% 73 min
May 497 74.7% 1.01% 72 min
June 413 66.8% 2.66% 86 min
July 419 56.3% 3.1% 80 min
August 412 75.1% 2.43% 85 min
September 397 79.8% 0.25% 75 min
October 478 66.9% 0% 68 min
November 427 69.4% 4.22% 76 min
December 364 56.5% 1.37% 88 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.