Best time to fly Paris (Roissy-en-France to Ingliston

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

Best month

March

84% on time · 162 flights

Worst month

January

53.5% on time · 131 flights

Month Flights On time Cancelled When late, by
January 131 53.5% 3.05% 0 min
February 136 78.5% 0.74% 0 min
March 162 84% 0% 0 min
April 152 82.9% 0% 0 min
May 154 72.5% 0.65% 0 min
June 311 64.8% 1.29% 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.