Best time to fly Springfield to Chicago

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

Best month

February

88.5% on time · 52 flights

Worst month

December

70.9% on time · 59 flights

Month Flights On time Cancelled When late, by
January 58 82.8% 0% 67 min
February 52 88.5% 0% 94 min
March 58 84.6% 10.34% 68 min
April 109 78.3% 2.75% 93 min
May 123 85.2% 0.81% 63 min
June 110 77.1% 0.91% 118 min
July 47 74.4% 8.51% 110 min
August 60 75.4% 5% 114 min
September 57 83.9% 1.75% 107 min
October 61 88.5% 0% 34 min
November 59 76.4% 6.78% 56 min
December 59 70.9% 6.78% 101 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.