Best time to fly Washington to Dallas/Fort Worth

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

Best month

October

89% on time · 349 flights

Worst month

June

67.5% on time · 384 flights

Month Flights On time Cancelled When late, by
January 267 81.2% 7.49% 100 min
February 260 84.1% 0.77% 97 min
March 314 82.7% 1.59% 123 min
April 294 77.2% 0.68% 91 min
May 333 68.1% 1.5% 96 min
June 384 67.5% 2.08% 104 min
July 317 73.1% 2.52% 96 min
August 311 79% 2.57% 109 min
September 331 81.3% 0.6% 88 min
October 349 89% 0.29% 52 min
November 288 85.4% 1.04% 140 min
December 270 75% 0.37% 71 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.