Best time to fly Bristol to Belfast

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

Best month

October

89.5% on time · 152 flights

Worst month

September

71.2% on time · 156 flights

Month Flights On time Cancelled When late, by
January 241 76.7% 2.07% 0 min
February 272 78.3% 0% 0 min
March 295 87.1% 0% 0 min
April 286 83.2% 0% 0 min
May 298 83.4% 0.67% 0 min
June 306 75% 0.65% 0 min
July 158 73.1% 1.27% 0 min
August 158 72.8% 0% 0 min
September 156 71.2% 0% 0 min
October 152 89.5% 0% 0 min
November 122 89.3% 0% 0 min
December 146 77.5% 2.74% 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.