Best time to fly Charlotte to Boston

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

Best month

November

83.7% on time · 348 flights

Worst month

September

60.1% on time · 318 flights

Month Flights On time Cancelled When late, by
January 290 82.9% 11.03% 79 min
February 275 80.6% 8% 67 min
March 327 78.9% 1.53% 82 min
April 338 82% 0% 48 min
May 354 78.2% 0% 62 min
June 352 81.1% 0.85% 64 min
July 359 62.6% 4.74% 72 min
August 354 76.4% 0.28% 50 min
September 318 60.1% 1.57% 64 min
October 370 68% 0.81% 79 min
November 348 83.7% 3.16% 62 min
December 331 81.8% 0.3% 53 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.