Best time to fly Appleton to Chicago

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

Best month

May

79.9% on time · 518 flights

Worst month

December

62.2% on time · 336 flights

Month Flights On time Cancelled When late, by
January 337 66.1% 2.97% 100 min
February 356 72.2% 1.12% 72 min
March 444 66.9% 8.11% 103 min
April 559 71.2% 5.01% 97 min
May 518 79.9% 0% 91 min
June 431 72.7% 2.09% 96 min
July 413 65.2% 2.42% 84 min
August 337 68.5% 2.97% 65 min
September 279 73.8% 0% 68 min
October 335 75.7% 0.3% 53 min
November 345 71.3% 6.96% 70 min
December 336 62.2% 6.25% 90 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.