Best time to fly Chicago to Colorado Springs

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

Best month

September

83.2% on time · 150 flights

Worst month

January

58.3% on time · 104 flights

Month Flights On time Cancelled When late, by
January 104 58.3% 0.96% 82 min
February 84 67.5% 0% 95 min
March 96 72.8% 2.08% 101 min
April 145 78.7% 2.76% 78 min
May 155 82.8% 1.94% 52 min
June 176 64.5% 2.27% 55 min
July 155 61% 0.65% 57 min
August 155 70% 1.94% 68 min
September 150 83.2% 0.67% 43 min
October 155 71.6% 0% 51 min
November 147 73.8% 0.68% 77 min
December 149 59.5% 0.67% 81 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.