Best time to fly Philadelphia to Louisville

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

Best month

April

89.8% on time · 60 flights

Worst month

November

61.5% on time · 13 flights

Month Flights On time Cancelled When late, by
January 26 76% 3.85% 70 min
February 45 88.1% 6.67% 24 min
March 62 85% 3.23% 88 min
April 60 89.8% 0% 55 min
May 72 88.7% 1.39% 51 min
June 63 83.3% 3.17% 80 min
July 56 72% 8.93% 64 min
August 36 67.6% 5.56% 123 min
September 66 89.1% 1.52% 65 min
October 86 79.1% 0% 74 min
November 13 61.5% 0% 57 min
December 17 70.6% 0% 60 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.