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 LHR record →

Best month

February

93.8% on time · 616 flights

Worst month

January

78.3% on time · 687 flights

Month Flights On time Cancelled When late, by
January 687 78.3% 4.66% 0 min
February 616 93.8% 0.32% 0 min
March 673 84.4% 3.86% 0 min
April 572 92.1% 0.52% 0 min
May 571 86.8% 0.35% 0 min
June 1,051 82% 1.24% 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.