Best time to fly Salt Lake City to Portland

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

Best month

May

92.6% on time · 192 flights

Worst month

July

79.7% on time · 247 flights

Month Flights On time Cancelled When late, by
January 177 86.8% 1.69% 52 min
February 172 88.8% 1.16% 50 min
March 194 88.5% 1.55% 57 min
April 186 90.2% 1.61% 51 min
May 192 92.6% 1.04% 66 min
June 215 86.4% 0.93% 48 min
July 247 79.7% 0.4% 81 min
August 222 89.1% 0.45% 65 min
September 176 92.6% 0% 58 min
October 211 90% 0% 70 min
November 189 86.5% 2.12% 46 min
December 201 84.4% 1% 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.