Best time to fly Chicago to Charleston

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

Best month

October

91.4% on time · 70 flights

Worst month

June

60.7% on time · 89 flights

Month Flights On time Cancelled When late, by
January 18 77.8% 0% 37 min
February 35 85.7% 0% 32 min
March 66 86.2% 1.52% 77 min
April 68 73.1% 1.47% 38 min
May 71 74.6% 0% 57 min
June 89 60.7% 0% 61 min
July 78 65.3% 2.56% 53 min
August 72 72.9% 2.78% 73 min
September 68 82.4% 0% 30 min
October 70 91.4% 0% 34 min
November 42 87.8% 2.38% 109 min
December 35 77.1% 0% 41 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.