Best time to fly London to Copenhagen

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

Best month

April

93.2% on time · 249 flights

Worst month

June

81.2% on time · 490 flights

Month Flights On time Cancelled When late, by
January 275 85.9% 2.18% 0 min
February 267 92.1% 0% 0 min
March 291 87.4% 4.81% 0 min
April 249 93.2% 0% 0 min
May 260 88.8% 0.38% 0 min
June 490 81.2% 1.43% 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.