Best time to fly Austin to San Francisco

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

Best month

August

85.5% on time · 251 flights

Worst month

May

53.2% on time · 253 flights

Month Flights On time Cancelled When late, by
January 203 77.9% 3.45% 66 min
February 182 77.3% 0% 67 min
March 210 85.2% 0.48% 76 min
April 220 60% 0% 61 min
May 253 53.2% 0.4% 70 min
June 243 55.1% 0% 60 min
July 241 72.1% 2.9% 59 min
August 251 85.5% 0.8% 48 min
September 228 83.3% 0% 49 min
October 252 84.8% 0.79% 73 min
November 251 81.9% 0.8% 80 min
December 261 83.4% 0.77% 75 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.