Best time to fly Glasgow to London

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

Best month

February

94% on time · 200 flights

Worst month

July

77.9% on time · 142 flights

Month Flights On time Cancelled When late, by
January 199 88% 4.02% 0 min
February 200 94% 0% 0 min
March 230 87% 0% 0 min
April 339 89.4% 0% 0 min
May 355 86.5% 0% 0 min
June 393 85.5% 0% 0 min
July 142 77.9% 1.41% 0 min
August 144 89.4% 1.39% 0 min
September 164 84.1% 0% 0 min
October 158 80.4% 0% 0 min
November 106 93.4% 0% 0 min
December 112 90.2% 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.