Best time to fly Medford to San Francisco

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

Best month

August

87.9% on time · 166 flights

Worst month

June

63.9% on time · 170 flights

Month Flights On time Cancelled When late, by
January 152 76.2% 3.29% 102 min
February 133 77.7% 1.5% 93 min
March 165 86% 0.61% 73 min
April 171 70% 0.58% 45 min
May 173 69.8% 0.58% 69 min
June 170 63.9% 0.59% 69 min
July 154 78.4% 0.65% 92 min
August 166 87.9% 0.6% 42 min
September 174 82.2% 0% 37 min
October 179 78.7% 0.56% 59 min
November 171 75% 1.75% 101 min
December 176 75.3% 2.84% 93 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.