Best time to fly Salt Lake City to Philadelphia

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

Best month

May

91.4% on time · 82 flights

Worst month

November

72.7% on time · 44 flights

Month Flights On time Cancelled When late, by
January 50 81.3% 4% 75 min
February 67 85.5% 7.46% 90 min
March 89 80.7% 1.12% 101 min
April 88 88.5% 0% 120 min
May 82 91.4% 1.22% 38 min
June 76 87.8% 2.63% 158 min
July 92 79.8% 6.52% 77 min
August 86 89.2% 2.33% 38 min
September 49 89.8% 0% 37 min
October 48 83.3% 0% 44 min
November 44 72.7% 0% 42 min
December 62 80.3% 1.61% 31 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.