Best time to fly London to Lisbon

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

Best month

February

87% on time · 131 flights

Worst month

March

72.1% on time · 153 flights

Month Flights On time Cancelled When late, by
January 139 84.2% 0% 0 min
February 131 87% 0% 0 min
March 153 72.1% 3.92% 0 min
April 134 75.6% 2.24% 0 min
May 137 75.9% 0% 0 min
June 252 74.1% 1.98% 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.