Best time to fly London to San Bartolomé

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

Best month

February

86.1% on time · 122 flights

Worst month

July

62% on time · 79 flights

Month Flights On time Cancelled When late, by
January 127 76.4% 0% 0 min
February 122 86.1% 0% 0 min
March 145 77.9% 0% 0 min
April 154 83.1% 0% 0 min
May 149 75.8% 0% 0 min
June 143 72.7% 0% 0 min
July 79 62% 0% 0 min
August 79 72.2% 0% 0 min
September 78 62.8% 0% 0 min
October 84 79.8% 0% 0 min
November 68 72.1% 0% 0 min
December 66 72.7% 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.