Best time to fly Colorado Springs to Chicago

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

Best month

October

95.2% on time · 62 flights

Worst month

May

57.7% on time · 26 flights

Month Flights On time Cancelled When late, by
January 32 90.6% 0% 30 min
February 26 92.3% 0% 21 min
March 27 92.6% 0% 26 min
April 26 73.1% 0% 27 min
May 26 57.7% 0% 46 min
June 75 68.5% 1.33% 44 min
July 107 79% 0% 43 min
August 66 78.5% 0% 51 min
September 60 88.3% 0% 32 min
October 62 95.2% 0% 34 min
November 48 76.1% 4.17% 56 min
December 46 80% 2.17% 59 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.