Best time to fly Riverton/Lander to Denver

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

Best month

September

92.4% on time · 120 flights

Worst month

June

74.2% on time · 120 flights

Month Flights On time Cancelled When late, by
January 124 83.5% 2.42% 249 min
February 111 89.2% 0% 214 min
March 124 83.9% 0% 140 min
April 120 78.3% 0% 171 min
May 124 82.5% 0.81% 141 min
June 120 74.2% 0% 98 min
July 124 79.5% 0.81% 97 min
August 124 77.7% 0.81% 133 min
September 120 92.4% 0% 104 min
October 124 79.8% 0% 152 min
November 118 84.5% 1.69% 141 min
December 124 90.3% 0% 96 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.