Best time to fly St. Louis to Dallas/Fort Worth

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

Best month

February

85.4% on time · 161 flights

Worst month

June

65.3% on time · 240 flights

Month Flights On time Cancelled When late, by
January 169 81.6% 10.06% 114 min
February 161 85.4% 0.62% 89 min
March 186 73.3% 2.69% 107 min
April 180 77.7% 2.22% 80 min
May 208 74.7% 4.33% 179 min
June 240 65.3% 5.42% 117 min
July 222 66% 3.15% 102 min
August 203 72.1% 2.46% 100 min
September 193 75.1% 2.07% 70 min
October 209 79% 1.91% 85 min
November 210 73.5% 4.76% 142 min
December 199 76.1% 1.01% 128 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.