Best time to fly New York to Des Moines

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

Best month

September

91.1% on time · 102 flights

Worst month

June

58.3% on time · 53 flights

Month Flights On time Cancelled When late, by
January 49 72.9% 2.04% 44 min
February 48 90.9% 6.25% 57 min
March 54 71.2% 3.7% 51 min
April 52 68.6% 0% 46 min
May 49 64.6% 0% 124 min
June 53 58.3% 5.66% 98 min
July 102 64.8% 12.75% 125 min
August 105 75% 11.43% 110 min
September 102 91.1% 0.98% 57 min
October 104 84.6% 0% 59 min
November 99 80.8% 0% 57 min
December 88 73.9% 0% 57 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.