Best time to fly Detroit to Portland

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

There is not yet enough of the year on record for this route to say anything about seasons. The months below are shown as recorded.

Month Flights On time Cancelled When late, by
January 4 75% 0% 79 min
March 24 36.4% 4.17% 40 min
April 30 76.7% 0% 131 min
May 31 60% 3.23% 134 min
June 44 75% 0% 46 min
July 57 63.2% 0% 54 min
August 50 80% 0% 42 min
September 42 90.5% 0% 58 min
October 48 87.2% 0% 31 min
November 29 58.6% 0% 59 min
December 31 13.3% 3.23% 43 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.