Best time to fly Pittsburgh to Boston

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

Best month

May

90.2% on time · 204 flights

Worst month

October

66.8% on time · 213 flights

Month Flights On time Cancelled When late, by
January 125 84.3% 8% 109 min
February 115 82.1% 7.83% 61 min
March 143 79.6% 0.7% 70 min
April 155 87.7% 0% 45 min
May 204 90.2% 0% 53 min
June 221 81.4% 4.98% 67 min
July 215 72.1% 5.12% 77 min
August 217 81.1% 2.3% 76 min
September 197 67.5% 3.05% 53 min
October 213 66.8% 1.88% 78 min
November 182 87.7% 1.65% 150 min
December 164 76.7% 0.61% 75 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.