Best time to fly San Francisco to Pittsburgh

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

Best month

November

93.7% on time · 95 flights

Worst month

July

75% on time · 115 flights

Month Flights On time Cancelled When late, by
January 73 88.7% 1.37% 60 min
February 56 92.9% 0% 48 min
March 66 84.8% 0% 100 min
April 94 92.6% 0% 37 min
May 116 81% 0% 34 min
June 111 86.5% 0% 46 min
July 115 75% 2.61% 36 min
August 107 79.4% 0% 38 min
September 98 87.8% 0% 66 min
October 97 92.8% 0% 24 min
November 95 93.7% 0% 43 min
December 88 89.7% 1.14% 46 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.