Best time to fly Marignane to London

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

Best month

February

96.1% on time · 51 flights

Worst month

June

66.1% on time · 231 flights

Month Flights On time Cancelled When late, by
January 52 74.5% 1.92% 0 min
February 51 96.1% 0% 0 min
March 61 79.7% 3.28% 0 min
April 123 90.2% 0% 0 min
May 115 79.5% 2.61% 0 min
June 231 66.1% 0.43% 0 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.