Best time to fly Washington to Dayton

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

Best month

September

84.5% on time · 171 flights

Worst month

February

51.2% on time · 180 flights

Month Flights On time Cancelled When late, by
January 180 58.2% 11.67% 71 min
February 180 51.2% 8.89% 85 min
March 197 68.1% 3.05% 98 min
April 192 72.8% 0.52% 80 min
May 198 64.2% 2.53% 67 min
June 164 63.5% 4.88% 103 min
July 158 64.4% 7.59% 94 min
August 160 71.9% 4.38% 92 min
September 171 84.5% 1.75% 61 min
October 179 77.7% 0% 60 min
November 185 76.8% 2.16% 73 min
December 150 57.4% 1.33% 94 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.