Best time to fly Oklahoma City to Chicago

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

Best month

May

81.9% on time · 236 flights

Worst month

March

68.2% on time · 207 flights

Month Flights On time Cancelled When late, by
January 185 77% 5.41% 107 min
February 170 81% 1.18% 83 min
March 207 68.2% 2.42% 100 min
April 230 80.5% 6.52% 60 min
May 236 81.9% 1.27% 88 min
June 237 74.4% 3.8% 92 min
July 226 69.2% 1.33% 109 min
August 215 71.6% 2.79% 78 min
September 217 80.5% 0.92% 62 min
October 235 76.1% 0% 89 min
November 218 73.4% 5.05% 90 min
December 218 68.4% 2.75% 124 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.