Best time to fly St. Louis to Valparaiso

Every month pooled across the years on record, so "July" means July generally rather than one particular July. Full STL to VPS 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
March 42 85.7% 0% 59 min
April 29 86.2% 0% 33 min
May 29 86.2% 0% 25 min
June 62 58.1% 0% 47 min
July 42 73.8% 0% 39 min
August 21 81% 0% 47 min
September 16 93.8% 0% 26 min
October 20 90% 0% 121 min
November 3 100% 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.