Best time to fly Chicago to Greer

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

Best month

April

84.3% on time · 143 flights

Worst month

July

62.4% on time · 170 flights

Month Flights On time Cancelled When late, by
January 120 64.2% 8.33% 63 min
February 122 72.1% 0% 47 min
March 150 69.1% 9.33% 52 min
April 143 84.3% 2.1% 61 min
May 185 80.1% 2.16% 61 min
June 156 77.1% 1.92% 122 min
July 170 62.4% 2.94% 102 min
August 147 74.8% 5.44% 72 min
September 128 80.3% 0.78% 95 min
October 173 69.4% 0% 54 min
November 165 73.1% 10.91% 67 min
December 140 65.7% 4.29% 87 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.