Best time to fly Lewiston to Seattle

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

Best month

April

96.7% on time · 60 flights

Worst month

February

79.6% on time · 56 flights

Month Flights On time Cancelled When late, by
January 62 91.8% 1.61% 132 min
February 56 79.6% 3.57% 73 min
March 62 96.6% 0% 203 min
April 60 96.7% 0% 97 min
May 62 95.2% 0% 167 min
June 60 86.7% 0% 26 min
July 62 95.2% 0% 123 min
August 61 93.4% 0% 37 min
September 60 90% 0% 76 min
October 62 91.9% 0% 65 min
November 60 83.3% 0% 29 min
December 62 83.6% 0% 138 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.