Best time to fly Seattle to Juneau

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

Best month

April

92% on time · 90 flights

Worst month

July

60.6% on time · 217 flights

Month Flights On time Cancelled When late, by
January 91 76.2% 4.4% 61 min
February 84 79.3% 1.19% 52 min
March 93 76.9% 1.08% 55 min
April 90 92% 0% 41 min
May 131 80.9% 0% 43 min
June 199 76.3% 0.5% 50 min
July 217 60.6% 1.84% 38 min
August 204 73.4% 0.49% 41 min
September 180 87% 1.67% 65 min
October 123 81.7% 2.44% 43 min
November 87 82.8% 0% 57 min
December 90 65.1% 4.44% 58 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.