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 LCY record →

Best month

April

91.2% on time · 480 flights

Worst month

September

77% on time · 232 flights

Month Flights On time Cancelled When late, by
January 431 89.8% 2.09% 0 min
February 464 91.1% 0.86% 0 min
March 496 83% 1.61% 0 min
April 480 91.2% 0.42% 0 min
May 469 83.9% 1.71% 0 min
June 442 77.6% 3.17% 0 min
July 209 88.4% 0.96% 0 min
August 193 77.2% 2.07% 0 min
September 232 77% 0.86% 0 min
October 253 88.8% 0.79% 0 min
November 256 87.4% 0.78% 0 min
December 201 87.8% 2.49% 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.