Best time to fly Houston to Tucson

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

Best month

January

86.4% on time · 86 flights

Worst month

July

54.2% on time · 56 flights

Month Flights On time Cancelled When late, by
January 86 86.4% 5.81% 38 min
February 103 86.4% 0% 64 min
March 97 81.9% 3.09% 63 min
April 95 77.9% 0% 54 min
May 58 86% 1.72% 52 min
July 56 54.2% 12.5% 87 min
August 56 85.5% 1.79% 130 min
September 59 74.6% 0% 49 min
October 76 84.2% 0% 36 min
November 29 86.2% 0% 43 min
December 43 69% 2.33% 30 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.