Best time to fly Washington to Hartford

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

Best month

April

92.5% on time · 159 flights

Worst month

July

68.3% on time · 106 flights

Month Flights On time Cancelled When late, by
January 143 90.6% 3.5% 50 min
February 149 90.9% 4.03% 47 min
March 167 80.9% 2.4% 58 min
April 159 92.5% 0% 55 min
May 197 77.2% 0% 77 min
June 149 80.3% 1.34% 70 min
July 106 68.3% 4.72% 55 min
August 122 81.5% 2.46% 65 min
September 170 86.5% 0% 32 min
October 173 89.6% 0% 35 min
November 129 82.7% 0.78% 61 min
December 136 86.8% 0% 45 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.