Best time to fly Philadelphia to Birmingham

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

Best month

November

88.7% on time · 71 flights

Worst month

May

64.9% on time · 120 flights

Month Flights On time Cancelled When late, by
January 58 81.5% 6.9% 101 min
February 54 78.8% 3.7% 104 min
March 62 83.9% 0% 143 min
April 107 81.1% 0% 108 min
May 120 64.9% 5% 79 min
June 108 65.3% 5.56% 89 min
July 102 70.2% 4.9% 103 min
August 120 71.6% 3.33% 83 min
September 109 79.8% 0% 67 min
October 121 87.6% 0% 84 min
November 71 88.7% 0% 55 min
December 65 72.3% 0% 100 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.