Best time to fly Portland to Spokane

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

Best month

April

93.2% on time · 44 flights

Worst month

January

79.8% on time · 91 flights

Month Flights On time Cancelled When late, by
January 91 79.8% 2.2% 46 min
February 80 92.3% 2.5% 37 min
March 65 84.4% 1.54% 48 min
April 44 93.2% 0% 63 min
May 69 85.5% 0% 48 min
June 102 89.2% 0% 34 min
July 58 89.7% 0% 52 min
August 72 90.3% 0% 75 min
September 88 85.2% 0% 24 min
October 88 81.6% 1.14% 50 min
November 94 89.2% 1.06% 36 min
December 113 81.1% 1.77% 38 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.