Best time to fly Los Angeles to Boston

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

Best month

November

84.9% on time · 768 flights

Worst month

May

77.5% on time · 835 flights

Month Flights On time Cancelled When late, by
January 692 80.4% 3.03% 88 min
February 638 82.7% 3.92% 80 min
March 744 81.7% 0.54% 69 min
April 728 82.4% 0.14% 62 min
May 835 77.5% 0% 59 min
June 847 81.8% 0.71% 102 min
July 870 79% 0.92% 76 min
August 901 82.1% 0.33% 63 min
September 803 80% 0% 72 min
October 890 80.5% 0.34% 88 min
November 768 84.9% 0.65% 77 min
December 751 77.6% 0.67% 76 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.