Best time to fly Bâle / Mulhouse to London

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

Best month

November

94.5% on time · 111 flights

Worst month

September

70.5% on time · 82 flights

Month Flights On time Cancelled When late, by
January 204 81.5% 1.96% 0 min
February 202 92% 0.99% 0 min
March 221 86.5% 2.71% 0 min
April 164 93.9% 0.61% 0 min
May 144 87.4% 0.69% 0 min
June 198 83.4% 2.53% 0 min
July 91 78.7% 2.2% 0 min
August 81 88.9% 0% 0 min
September 82 70.5% 4.88% 0 min
October 97 83.2% 2.06% 0 min
November 111 94.5% 0.9% 0 min
December 112 81.8% 1.79% 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.