Best time to fly Los Angeles to Chicago

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

Best month

February

89.2% on time · 167 flights

Worst month

July

73% on time · 292 flights

Month Flights On time Cancelled When late, by
January 192 85.9% 0% 51 min
February 167 89.2% 0% 51 min
March 210 78.7% 2.38% 36 min
April 213 85% 0.47% 51 min
May 220 81.4% 0% 46 min
June 247 78.9% 0% 48 min
July 292 73% 0% 61 min
August 246 83.9% 0.41% 44 min
September 235 88.9% 0% 50 min
October 238 82.4% 0% 34 min
November 210 86.4% 0.95% 51 min
December 221 83.6% 0% 53 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.