Best time to fly Las Vegas to Chicago

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

Best month

February

84.3% on time · 394 flights

Worst month

July

71% on time · 479 flights

Month Flights On time Cancelled When late, by
January 356 78.7% 0.56% 88 min
February 394 84.3% 0% 49 min
March 489 71.1% 3.07% 92 min
April 504 75.9% 1.59% 69 min
May 483 79% 0% 68 min
June 395 75.3% 1.77% 114 min
July 479 71% 1.67% 65 min
August 485 77.8% 2.06% 62 min
September 481 77.6% 0.62% 91 min
October 482 78% 0% 67 min
November 390 74.1% 2.56% 91 min
December 359 76.1% 0.84% 84 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.