Best time to fly Boston to Indianapolis

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

Best month

August

88.8% on time · 352 flights

Worst month

May

79.4% on time · 340 flights

Month Flights On time Cancelled When late, by
January 329 88.2% 4.86% 128 min
February 305 83% 5.25% 60 min
March 339 83.5% 1.18% 61 min
April 332 80.7% 0% 58 min
May 340 79.4% 0% 56 min
June 352 82.1% 0.28% 84 min
July 357 79.8% 1.68% 80 min
August 352 88.8% 3.69% 76 min
September 331 83.5% 0.91% 72 min
October 346 85.6% 1.45% 59 min
November 325 88% 0.31% 56 min
December 311 85.4% 0.96% 73 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.