Best time to fly Phoenix to San Francisco

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

Best month

March

83.2% on time · 454 flights

Worst month

June

37.3% on time · 383 flights

Month Flights On time Cancelled When late, by
January 377 78.4% 1.86% 93 min
February 360 80.8% 0% 69 min
March 454 83.2% 0.22% 61 min
April 432 54.1% 0.23% 56 min
May 418 45.1% 0.24% 56 min
June 383 37.3% 0% 65 min
July 356 64.5% 0.28% 56 min
August 341 73% 0% 70 min
September 342 76.9% 1.17% 65 min
October 366 71% 0% 52 min
November 390 75.9% 2.31% 66 min
December 425 74.2% 0.47% 87 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.