Best time to fly Portland to Kona

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

Best month

May

95.9% on time · 49 flights

Worst month

December

77% on time · 62 flights

Month Flights On time Cancelled When late, by
January 62 91.9% 0% 38 min
February 56 82.1% 0% 29 min
March 62 79% 0% 50 min
April 56 94.6% 0% 49 min
May 49 95.9% 0% 107 min
June 55 85.5% 0% 44 min
July 62 91.9% 0% 119 min
August 62 88.7% 0% 42 min
September 59 84.7% 0% 49 min
October 62 80.3% 0% 38 min
November 60 83.3% 0% 36 min
December 62 77% 0% 39 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.