Best time to fly Detroit to Houston

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

Best month

September

94.5% on time · 181 flights

Worst month

December

61.4% on time · 170 flights

Month Flights On time Cancelled When late, by
January 130 70.9% 1.54% 69 min
February 149 85.1% 0% 53 min
March 203 75.9% 3.45% 78 min
April 181 79.4% 0.55% 79 min
May 182 73.9% 1.1% 51 min
June 173 71.1% 0% 61 min
July 199 80.6% 1.51% 70 min
August 202 86% 0.99% 46 min
September 181 94.5% 0% 58 min
October 168 91.7% 0% 47 min
November 191 82.5% 1.05% 64 min
December 170 61.4% 2.35% 58 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.