Best time to fly Ketchikan to Seattle

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

Best month

May

96.4% on time · 112 flights

Worst month

August

70.4% on time · 143 flights

Month Flights On time Cancelled When late, by
January 91 77.2% 13.19% 79 min
February 84 84.8% 5.95% 55 min
March 93 73.6% 2.15% 85 min
April 90 91.1% 0% 117 min
May 112 96.4% 0% 46 min
June 141 88.7% 0% 84 min
July 155 74.5% 1.29% 68 min
August 143 70.4% 0.7% 45 min
September 120 84.7% 1.67% 86 min
October 96 93.7% 1.04% 178 min
November 88 88% 5.68% 40 min
December 91 72.1% 5.49% 68 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.