Best time to fly Charlotte to Washington

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

Best month

October

87.1% on time · 333 flights

Worst month

July

69.1% on time · 338 flights

Month Flights On time Cancelled When late, by
January 345 86.4% 8.12% 74 min
February 326 77.1% 3.37% 62 min
March 328 80.7% 3.66% 73 min
April 396 85% 0.25% 69 min
May 373 81.7% 1.88% 63 min
June 268 73.1% 2.61% 91 min
July 338 69.1% 5.33% 82 min
August 340 74.5% 2.65% 82 min
September 319 86.4% 0.63% 71 min
October 333 87.1% 0% 51 min
November 398 87.1% 1.01% 68 min
December 357 72.5% 0.28% 61 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.