Best time to fly Knoxville to Washington

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

Best month

September

81.9% on time · 172 flights

Worst month

February

57.1% on time · 161 flights

Month Flights On time Cancelled When late, by
January 162 66.4% 9.88% 143 min
February 161 57.1% 8.07% 94 min
March 182 61% 4.95% 109 min
April 177 71.5% 2.26% 127 min
May 187 80.3% 3.74% 75 min
June 178 74.8% 7.87% 100 min
July 181 70.4% 11.05% 93 min
August 177 76.3% 3.95% 116 min
September 172 81.9% 0.58% 71 min
October 177 78% 0% 65 min
November 191 80.1% 1.57% 95 min
December 142 61.6% 2.11% 135 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.