Best time to fly Peoria to Chicago

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

Best month

September

81.4% on time · 312 flights

Worst month

March

62.7% on time · 331 flights

Month Flights On time Cancelled When late, by
January 308 71.4% 1.95% 90 min
February 288 69.7% 0.35% 87 min
March 331 62.7% 4.23% 80 min
April 499 71.7% 5.01% 105 min
May 401 75.7% 1.25% 113 min
June 396 73.6% 2.27% 71 min
July 305 68.9% 1.64% 97 min
August 291 72% 3.09% 104 min
September 312 81.4% 0.32% 61 min
October 319 77.4% 0% 69 min
November 255 72.6% 9.8% 90 min
December 282 64.6% 3.9% 84 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.