Best time to fly Houston to Atlanta

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

Best month

September

85.9% on time · 765 flights

Worst month

July

65.8% on time · 799 flights

Month Flights On time Cancelled When late, by
January 718 80.9% 6.13% 90 min
February 697 83.3% 0.29% 54 min
March 806 71.5% 3.72% 66 min
April 809 78.8% 0.74% 74 min
May 841 69.7% 0.59% 81 min
June 786 66.3% 2.42% 85 min
July 799 65.8% 5.88% 87 min
August 797 79.5% 1.63% 65 min
September 765 85.9% 1.05% 60 min
October 860 83.2% 0.35% 56 min
November 803 81.2% 1.49% 64 min
December 742 76.1% 1.75% 67 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.