Best time to fly Chicago to Dallas

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

Best month

October

91.2% on time · 172 flights

Worst month

July

65.3% on time · 178 flights

Month Flights On time Cancelled When late, by
January 103 84.8% 3.88% 73 min
February 99 83.8% 0% 40 min
March 117 77.4% 0.85% 85 min
April 116 69.6% 2.59% 51 min
May 119 68.1% 2.52% 81 min
June 89 68.5% 0% 60 min
July 178 65.3% 0% 63 min
August 160 79.7% 0.63% 52 min
September 154 84.8% 0.65% 53 min
October 172 91.2% 0% 31 min
November 114 79.6% 0% 98 min
December 119 76.5% 0% 95 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.