Best time to fly Billings to Chicago

Every month pooled across the years on record, so "July" means July generally rather than one particular July. Full BIL to ORD 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
May 21 85.7% 0% 37 min
June 111 75.5% 0% 88 min
July 124 70.5% 0% 120 min
August 124 81.5% 0.81% 116 min
September 120 83.3% 0% 53 min
October 67 82.1% 0% 81 min
November 1 100% 0%

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.