Best time to fly San Francisco to Tucson

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

Best month

April

86.4% on time · 177 flights

Worst month

December

77.2% on time · 182 flights

Month Flights On time Cancelled When late, by
January 174 83% 1.72% 92 min
February 159 80.5% 0% 63 min
March 173 84.8% 0.58% 54 min
April 177 86.4% 0% 50 min
May 173 83.2% 0% 57 min
June 146 81.5% 0% 50 min
July 137 85.2% 0% 58 min
August 131 82.4% 0% 51 min
September 120 85.8% 0% 70 min
October 141 83.7% 0% 46 min
November 209 80.8% 0.48% 54 min
December 182 77.2% 1.1% 99 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.