Best time to fly Dallas to Washington

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

Best month

December

78.5% on time · 149 flights

Worst month

March

54.5% on time · 151 flights

Month Flights On time Cancelled When late, by
January 146 77% 6.85% 82 min
February 132 64.3% 2.27% 39 min
March 151 54.5% 1.99% 66 min
April 143 64.3% 0% 66 min
May 145 62.9% 1.38% 76 min
June 146 58.5% 2.05% 67 min
July 150 63.6% 2% 62 min
August 146 76.4% 1.37% 50 min
September 142 77.5% 0% 43 min
October 146 64.8% 0% 46 min
November 139 74.1% 2.88% 93 min
December 149 78.5% 0% 41 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.