Best time to fly Nashville to St. Louis

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

Best month

January

92.5% on time · 97 flights

Worst month

May

65.5% on time · 114 flights

Month Flights On time Cancelled When late, by
January 97 92.5% 4.12% 44 min
February 94 84% 0% 32 min
March 110 85.2% 1.82% 54 min
April 111 76.6% 0% 55 min
May 114 65.5% 0.88% 48 min
June 108 76.6% 0.93% 51 min
July 100 75.8% 1% 58 min
August 109 90.7% 1.83% 40 min
September 108 90.7% 0% 35 min
October 119 69.7% 0% 47 min
November 102 80.4% 0% 55 min
December 102 78.2% 0.98% 78 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.