Best time to fly Pisa (PI) to London

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

Best month

November

90% on time · 60 flights

Worst month

July

38.6% on time · 101 flights

Month Flights On time Cancelled When late, by
January 98 84.7% 0% 0 min
February 116 88.8% 0% 0 min
March 131 87.8% 0% 0 min
April 189 75.7% 0% 0 min
May 194 61.9% 0% 0 min
June 195 47.9% 0.51% 0 min
July 101 38.6% 0% 0 min
August 103 50.5% 0% 0 min
September 90 42.7% 1.11% 0 min
October 91 56% 0% 0 min
November 60 90% 0% 0 min
December 66 81.8% 0% 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.