Best time to fly Houston to Des Moines

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

Best month

February

92.7% on time · 56 flights

Worst month

August

54% on time · 52 flights

Month Flights On time Cancelled When late, by
January 52 86.3% 1.92% 26 min
February 56 92.7% 1.79% 35 min
March 42 77.5% 4.76% 62 min
April 55 69.1% 0% 67 min
May 62 67.7% 0% 75 min
June 60 63.3% 0% 83 min
July 64 55% 6.25% 70 min
August 52 54% 1.92% 51 min
September 37 81.1% 0% 38 min
October 69 87% 0% 41 min
November 52 72.5% 0% 59 min
December 36 72.2% 0% 49 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.