Best time to fly Portland to Oakland

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

Best month

January

92.7% on time · 96 flights

Worst month

July

60.3% on time · 119 flights

Month Flights On time Cancelled When late, by
January 96 92.7% 0% 47 min
February 97 87.5% 1.03% 65 min
March 100 75% 0% 55 min
April 89 77.5% 0% 45 min
May 111 79.3% 0% 41 min
June 124 70.2% 0% 56 min
July 119 60.3% 1.68% 67 min
August 104 79.8% 0% 61 min
September 99 70.7% 0% 33 min
October 107 74.8% 0% 44 min
November 112 82.1% 5.36% 57 min
December 121 78.5% 0% 41 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.