Best time to fly Chicago to Tulsa

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

Best month

September

84.8% on time · 299 flights

Worst month

July

62.6% on time · 356 flights

Month Flights On time Cancelled When late, by
January 268 73.7% 3.36% 68 min
February 263 72.9% 1.9% 73 min
March 329 77.5% 3.34% 68 min
April 333 75.5% 3% 68 min
May 330 74.3% 0.3% 56 min
June 354 71% 1.69% 67 min
July 356 62.6% 1.97% 87 min
August 313 78.3% 0.96% 68 min
September 299 84.8% 0.67% 62 min
October 304 83.9% 0% 68 min
November 299 76.5% 3.34% 71 min
December 318 70.2% 0.63% 85 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.