Best time to fly Detroit to Birmingham

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

Best month

May

84.8% on time · 46 flights

Worst month

January

55% on time · 41 flights

Month Flights On time Cancelled When late, by
January 41 55% 2.44% 83 min
February 25 68% 0% 42 min
March 72 60.3% 5.56% 82 min
April 99 78.8% 0% 64 min
May 46 84.8% 0% 80 min
June 86 78.8% 0% 53 min
July 118 62.4% 0.85% 71 min
August 82 69.5% 0% 70 min
September 52 69.2% 0% 35 min
October 56 82.1% 0% 49 min
November 57 78.9% 0% 82 min
December 57 68.4% 0% 101 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.