Best time to fly Portland to Las Vegas

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

Best month

January

85.7% on time · 225 flights

Worst month

December

73.2% on time · 239 flights

Month Flights On time Cancelled When late, by
January 225 85.7% 0.89% 51 min
February 206 85.4% 0% 42 min
March 257 81.3% 0.39% 43 min
April 239 80.6% 0.42% 48 min
May 237 85.1% 0.42% 45 min
June 250 77.2% 1.2% 55 min
July 303 76.7% 0.66% 68 min
August 274 82.4% 0.36% 44 min
September 265 79.5% 0% 51 min
October 250 76.2% 0.8% 51 min
November 238 80.9% 1.26% 62 min
December 239 73.2% 0% 64 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.