Best time to fly Norfolk to Chicago

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

Best month

May

85.1% on time · 210 flights

Worst month

July

63.4% on time · 152 flights

Month Flights On time Cancelled When late, by
January 106 65.7% 5.66% 64 min
February 125 74.4% 2.4% 58 min
March 155 71.4% 4.52% 82 min
April 172 78.2% 4.07% 92 min
May 210 85.1% 0.48% 79 min
June 201 80.3% 3.98% 74 min
July 152 63.4% 3.29% 77 min
August 126 74.6% 3.17% 68 min
September 143 80.1% 0% 39 min
October 170 75.3% 0% 51 min
November 145 77.3% 2.76% 66 min
December 160 75.8% 1.88% 75 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.