Best time to fly Des Moines to Houston

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

Best month

October

92.8% on time · 69 flights

Worst month

December

84.2% on time · 38 flights

Month Flights On time Cancelled When late, by
January 50 87.5% 4% 69 min
February 56 87.3% 1.79% 222 min
March 42 89.7% 4.76% 80 min
April 55 87.3% 0% 23 min
May 62 86.9% 1.61% 72 min
June 60 86.7% 0% 92 min
July 64 84.7% 7.81% 62 min
August 53 92.5% 0% 85 min
September 36 91.7% 0% 42 min
October 69 92.8% 0% 24 min
November 52 88% 3.85% 60 min
December 38 84.2% 0% 77 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.