Best time to fly New York to Washington

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

Best month

September

82.9% on time · 262 flights

Worst month

February

52.6% on time · 168 flights

Month Flights On time Cancelled When late, by
January 181 57.4% 9.94% 66 min
February 168 52.6% 8.33% 62 min
March 186 53.9% 2.15% 85 min
April 156 71.2% 0% 66 min
May 205 68.8% 2.93% 65 min
June 210 69.7% 7.14% 73 min
July 217 69.6% 16.13% 89 min
August 217 79.7% 2.3% 76 min
September 262 82.9% 1.53% 73 min
October 249 73.4% 2.81% 65 min
November 263 60.2% 6.46% 69 min
December 214 64% 4.67% 68 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.