Best time to fly Spokane to Seattle

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

Best month

May

91.5% on time · 415 flights

Worst month

July

79.4% on time · 544 flights

Month Flights On time Cancelled When late, by
January 437 82.6% 2.52% 59 min
February 400 91.2% 0.5% 85 min
March 418 88% 2.15% 65 min
April 387 90.7% 0% 69 min
May 415 91.5% 0.72% 73 min
June 375 88% 0.27% 50 min
July 544 79.4% 0.92% 46 min
August 504 81.2% 0.6% 44 min
September 436 85.6% 0% 43 min
October 447 85.8% 0.67% 54 min
November 424 89.2% 3.3% 56 min
December 396 81.3% 1.01% 51 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.