Best time to fly Houston to Boston

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

Best month

February

88.4% on time · 123 flights

Worst month

October

56.4% on time · 189 flights

Month Flights On time Cancelled When late, by
January 115 85.3% 5.22% 52 min
February 123 88.4% 8.94% 74 min
March 148 76.9% 0.68% 65 min
April 151 73.5% 0% 51 min
May 178 72.5% 0% 62 min
June 187 67.9% 0% 67 min
July 216 70.3% 1.85% 93 min
August 196 71.8% 0.51% 75 min
September 158 57.3% 0.63% 75 min
October 189 56.4% 0% 80 min
November 189 76.6% 0.53% 71 min
December 175 86.3% 0% 85 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.