Best time to fly Houston to Ontario

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

There is not yet enough of the year on record for this route to say anything about seasons. The months below are shown as recorded.

Month Flights On time Cancelled When late, by
January 41 90.2% 0% 66 min
February 36 91.7% 0% 42 min
March 40 80% 0% 106 min
April 39 84.6% 0% 60 min
May 61 85.2% 0% 74 min
June 60 70% 0% 72 min
July 39 56.4% 0% 71 min
August 40 61.5% 2.5% 66 min
September 43 81.4% 0% 57 min
October 48 68.8% 0% 41 min
November 47 68.1% 0% 64 min
December 44 72.1% 0% 29 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.