Best time to fly Las Vegas to San Francisco

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

Best month

January

80% on time · 1,044 flights

Worst month

June

57.3% on time · 1,004 flights

Month Flights On time Cancelled When late, by
January 1,044 80% 0.38% 67 min
February 912 72.2% 0.11% 73 min
March 1,023 77.7% 0.39% 58 min
April 1,003 64.2% 0.1% 50 min
May 1,055 57.8% 0.38% 58 min
June 1,004 57.3% 0.7% 60 min
July 939 66.3% 2.56% 63 min
August 1,010 72.3% 0.5% 53 min
September 1,051 68.5% 0.57% 51 min
October 1,094 67% 0.46% 53 min
November 1,039 66.3% 1.44% 62 min
December 1,044 68.5% 0.38% 66 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.