Best time to fly New York to Houston

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

Best month

September

86.3% on time · 706 flights

Worst month

July

65.9% on time · 759 flights

Month Flights On time Cancelled When late, by
January 663 80.1% 5.28% 62 min
February 545 80.7% 3.12% 78 min
March 596 81.8% 4.36% 92 min
April 730 81.7% 0.55% 66 min
May 716 72.1% 1.12% 75 min
June 701 69.5% 1.57% 90 min
July 759 65.9% 5.8% 110 min
August 739 80.6% 2.84% 104 min
September 706 86.3% 0.14% 68 min
October 753 81.4% 1.2% 71 min
November 727 82.4% 0.83% 77 min
December 730 74.8% 2.05% 93 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.