Best time to fly Charleston to Chicago

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

Best month

August

83.5% on time · 139 flights

Worst month

July

68.7% on time · 171 flights

Month Flights On time Cancelled When late, by
January 145 80.7% 2.07% 59 min
February 152 77.7% 1.97% 56 min
March 209 70.5% 5.74% 59 min
April 194 74.2% 2.58% 119 min
May 208 79.2% 0.48% 82 min
June 202 77.9% 3.96% 76 min
July 171 68.7% 2.92% 52 min
August 139 83.5% 3.6% 90 min
September 145 79.3% 0% 64 min
October 176 82.4% 0% 75 min
November 178 74.3% 3.37% 78 min
December 172 73.7% 2.33% 82 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.