Best time to fly Chicago to Springfield

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

Best month

September

84.9% on time · 337 flights

Worst month

December

65% on time · 232 flights

Month Flights On time Cancelled When late, by
January 190 71.9% 2.11% 64 min
February 159 72.7% 3.14% 59 min
March 242 70% 2.07% 73 min
April 291 75.6% 1.72% 59 min
May 260 84% 1.15% 50 min
June 281 76.5% 3.2% 58 min
July 275 66.2% 0.73% 69 min
August 325 76% 0.92% 67 min
September 337 84.9% 0% 68 min
October 315 80.1% 0% 69 min
November 211 75.7% 3.32% 87 min
December 232 65% 2.59% 102 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.