Best time to fly Denver to Salt Lake City

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

Best month

September

84.3% on time · 1,292 flights

Worst month

July

65.2% on time · 1,390 flights

Month Flights On time Cancelled When late, by
January 1,282 79.3% 0.16% 50 min
February 1,230 78.9% 0.41% 63 min
March 1,341 82.5% 0.37% 71 min
April 1,273 80.4% 0.31% 67 min
May 1,310 77.4% 0.08% 62 min
June 1,321 67% 0.15% 63 min
July 1,390 65.2% 1.87% 70 min
August 1,364 72.5% 0.59% 76 min
September 1,292 84.3% 0% 56 min
October 1,324 83.7% 0% 55 min
November 1,190 82.3% 1.51% 52 min
December 1,274 77.8% 0.16% 58 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.