Best time to fly Philadelphia to Los Angeles

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

Best month

September

87.1% on time · 211 flights

Worst month

December

66.5% on time · 175 flights

Month Flights On time Cancelled When late, by
January 154 77.1% 5.84% 69 min
February 139 79.5% 4.32% 53 min
March 155 86.2% 1.29% 93 min
April 198 80.8% 0% 62 min
May 224 80.4% 0% 69 min
June 235 73.5% 2.13% 108 min
July 263 70.1% 3.42% 83 min
August 252 75.7% 0.4% 80 min
September 211 87.1% 0.47% 48 min
October 243 83.5% 0% 57 min
November 169 81.5% 0% 43 min
December 175 66.5% 0.57% 46 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.