Best time to fly Pittsburgh to Chicago

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

Best month

February

85.5% on time · 257 flights

Worst month

December

68.9% on time · 303 flights

Month Flights On time Cancelled When late, by
January 271 72.5% 4.06% 95 min
February 257 85.5% 0.39% 64 min
March 281 71.3% 3.2% 114 min
April 347 76.9% 2.88% 97 min
May 396 83.7% 1.01% 96 min
June 366 80.2% 3.01% 134 min
July 337 72.8% 1.78% 92 min
August 343 84.9% 2.62% 115 min
September 345 82.3% 0.29% 63 min
October 372 81.9% 0.27% 50 min
November 332 78.2% 4.52% 116 min
December 303 68.9% 0.33% 78 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.