Best time to fly Lisbon to London

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

Best month

May

73% on time · 138 flights

Worst month

March

59.9% on time · 153 flights

Month Flights On time Cancelled When late, by
January 139 69.8% 0% 0 min
February 132 72.3% 1.52% 0 min
March 153 59.9% 3.92% 0 min
April 134 61.8% 2.24% 0 min
May 138 73% 0.72% 0 min
June 253 69.9% 2.77% 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.