Best time to fly London to Rotterdam

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

Best month

February

90.4% on time · 137 flights

Worst month

August

69% on time · 72 flights

Month Flights On time Cancelled When late, by
January 130 82.9% 0.77% 0 min
February 137 90.4% 0.73% 0 min
March 152 81% 3.29% 0 min
April 157 84.7% 0% 0 min
May 150 77.9% 0.67% 0 min
June 140 78.5% 3.57% 0 min
July 76 73% 2.63% 0 min
August 72 69% 1.39% 0 min
September 83 75.9% 0% 0 min
October 92 77.2% 0% 0 min
November 74 87.8% 0% 0 min
December 69 77.6% 2.9% 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.