Best time to fly Washington to Salt Lake City

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

Best month

November

90% on time · 60 flights

Worst month

June

61% on time · 60 flights

Month Flights On time Cancelled When late, by
January 62 73.8% 1.61% 44 min
February 56 66.7% 3.57% 82 min
March 62 67.2% 1.61% 54 min
April 60 78.3% 0% 41 min
May 62 77% 1.61% 48 min
June 60 61% 1.67% 84 min
July 62 66.1% 4.84% 188 min
August 62 85.2% 0% 91 min
September 60 85% 0% 66 min
October 62 87.1% 0% 52 min
November 60 90% 0% 30 min
December 62 78.7% 0% 56 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.