Best time to fly Los Angeles to St. Louis

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

Best month

May

84.4% on time · 162 flights

Worst month

June

72.5% on time · 178 flights

Month Flights On time Cancelled When late, by
January 132 81.1% 3.79% 40 min
February 121 81.8% 0% 48 min
March 159 77.6% 1.26% 65 min
April 159 84.1% 1.26% 49 min
May 162 84.4% 0.62% 62 min
June 178 72.5% 0% 62 min
July 207 75% 0.97% 67 min
August 187 77.4% 0.53% 43 min
September 171 83.6% 0% 62 min
October 203 84.2% 0% 52 min
November 191 77.4% 0.52% 52 min
December 188 81.9% 0% 54 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.