Best time to fly San Francisco to San Diego

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

Best month

January

81.9% on time · 1,027 flights

Worst month

June

63.4% on time · 1,180 flights

Month Flights On time Cancelled When late, by
January 1,027 81.9% 1.07% 74 min
February 895 75.5% 1.23% 56 min
March 1,030 77% 0.58% 54 min
April 1,041 70.4% 0.19% 55 min
May 1,126 67.8% 0.8% 56 min
June 1,180 63.4% 1.1% 57 min
July 1,121 68.9% 1.25% 54 min
August 1,161 71.2% 0.26% 55 min
September 1,156 73.2% 0.87% 48 min
October 1,237 65.7% 1.13% 60 min
November 1,149 67.5% 1.91% 64 min
December 1,081 65% 1.67% 71 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.