Best time to fly New York to Raleigh/Durham

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

Best month

May

86% on time · 164 flights

Worst month

July

63.3% on time · 217 flights

Month Flights On time Cancelled When late, by
January 184 71.2% 11.41% 70 min
February 185 74.7% 12.43% 70 min
March 197 73.8% 1.02% 82 min
April 156 84% 0% 54 min
May 164 86% 0% 94 min
June 186 75.3% 4.3% 72 min
July 217 63.3% 11.98% 84 min
August 201 84.8% 1.49% 57 min
September 197 81.4% 1.52% 67 min
October 195 72.6% 2.56% 48 min
November 248 77.3% 6.05% 58 min
December 233 68.3% 5.15% 60 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.