Best time to fly Chicago to Kalamazoo

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

Best month

September

87.1% on time · 86 flights

Worst month

June

55.9% on time · 63 flights

Month Flights On time Cancelled When late, by
January 66 66.7% 3.03% 74 min
February 73 75.3% 0% 90 min
March 93 73.6% 6.45% 61 min
April 90 74.4% 4.44% 78 min
May 79 77.9% 1.27% 59 min
June 63 55.9% 6.35% 81 min
July 88 60.7% 4.55% 49 min
August 85 79.5% 2.35% 40 min
September 86 87.1% 1.16% 61 min
October 91 80% 0% 37 min
November 87 86.7% 13.79% 64 min
December 89 68.7% 6.74% 88 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.