Best time to fly Indianapolis to Washington

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

Best month

September

84.3% on time · 340 flights

Worst month

December

68.8% on time · 302 flights

Month Flights On time Cancelled When late, by
January 336 76.5% 8.63% 62 min
February 319 69.7% 10.66% 57 min
March 349 73.2% 2.87% 59 min
April 333 79.5% 0.3% 52 min
May 359 80% 2.23% 77 min
June 345 77.1% 4.64% 83 min
July 346 75.4% 6.36% 96 min
August 342 81.2% 2.05% 81 min
September 340 84.3% 0.59% 48 min
October 351 84% 0.28% 47 min
November 331 81.1% 2.42% 63 min
December 302 68.8% 0.99% 60 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.