Best time to fly Key West to Philadelphia

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

Best month

October

85.4% on time · 85 flights

Worst month

July

47.2% on time · 57 flights

Month Flights On time Cancelled When late, by
January 116 70.4% 5.17% 106 min
February 108 66.7% 5.56% 123 min
March 121 65.8% 2.48% 196 min
April 96 74.7% 0% 163 min
May 66 63.6% 0% 141 min
June 60 54.4% 1.67% 162 min
July 57 47.2% 3.51% 127 min
August 54 52.1% 5.56% 179 min
September 58 82.1% 3.45% 163 min
October 85 85.4% 3.53% 94 min
November 108 81% 2.78% 91 min
December 112 73.6% 1.79% 92 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.