Best time to fly Colombo to London

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

Best month

September

96.7% on time · 30 flights

Worst month

April

56.7% on time · 60 flights

Month Flights On time Cancelled When late, by
January 78 67.9% 0% 0 min
February 72 76.4% 0% 0 min
March 87 74.1% 2.3% 0 min
April 60 56.7% 0% 0 min
May 62 67.7% 0% 0 min
June 60 73.3% 0% 0 min
July 31 90.3% 0% 0 min
August 31 93.5% 0% 0 min
September 30 96.7% 0% 0 min
October 32 81.3% 0% 0 min
November 40 87.5% 0% 0 min
December 39 71.8% 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.