Best time to fly Kansas City to Philadelphia

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

Best month

May

90.2% on time · 93 flights

Worst month

July

63.9% on time · 89 flights

Month Flights On time Cancelled When late, by
January 62 83.9% 9.68% 121 min
February 55 85.7% 10.91% 112 min
March 62 86.2% 6.45% 84 min
April 84 88.1% 0% 231 min
May 93 90.2% 1.08% 43 min
June 90 88.9% 0% 100 min
July 89 63.9% 5.62% 106 min
August 90 78.8% 5.56% 46 min
September 78 78.2% 0% 49 min
October 83 78.3% 0% 125 min
November 58 79.3% 0% 120 min
December 59 68.5% 8.47% 196 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.