Best time to fly London to Rome

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

Best month

February

91.8% on time · 207 flights

Worst month

June

71.4% on time · 475 flights

Month Flights On time Cancelled When late, by
January 209 76.3% 0.96% 0 min
February 207 91.8% 0% 0 min
March 234 74.8% 3.42% 0 min
April 261 85.4% 0% 0 min
May 257 79.3% 0.39% 0 min
June 475 71.4% 1.26% 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.