Best time to fly Bozeman to Chicago

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

Best month

May

87.2% on time · 95 flights

Worst month

July

65.5% on time · 142 flights

Month Flights On time Cancelled When late, by
January 103 68.6% 0.97% 71 min
February 96 80% 0% 115 min
March 116 71.7% 1.72% 100 min
April 47 68.9% 2.13% 58 min
May 95 87.2% 1.05% 61 min
June 150 71.1% 0.67% 109 min
July 142 65.5% 1.41% 94 min
August 144 70.8% 2.78% 95 min
September 133 76.7% 0% 62 min
October 115 83.3% 0.87% 40 min
November 31 67.7% 0% 103 min
December 83 67.5% 0% 127 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.