Best time to fly Las Vegas to Seattle

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

Best month

February

93.4% on time · 415 flights

Worst month

August

76.5% on time · 489 flights

Month Flights On time Cancelled When late, by
January 459 86.9% 0.44% 49 min
February 415 93.4% 0.72% 82 min
March 478 86.9% 2.51% 76 min
April 475 83.9% 0.42% 64 min
May 496 80.5% 0.81% 49 min
June 477 77.8% 0.21% 69 min
July 521 80.8% 0.96% 58 min
August 489 76.5% 0% 57 min
September 441 82.4% 0.23% 59 min
October 485 77.8% 2.47% 79 min
November 445 84.9% 1.8% 64 min
December 468 77.4% 0.64% 60 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.