Best time to fly New York to Denver

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

Best month

September

83.1% on time · 797 flights

Worst month

June

60.7% on time · 788 flights

Month Flights On time Cancelled When late, by
January 754 82.4% 2.12% 45 min
February 674 72.1% 3.71% 72 min
March 769 75.4% 2.86% 76 min
April 755 74.9% 0.13% 60 min
May 773 73.2% 1.29% 74 min
June 788 60.7% 2.66% 73 min
July 813 65.8% 4.31% 102 min
August 812 74.3% 3.08% 100 min
September 797 83.1% 0.25% 77 min
October 807 79.7% 0.99% 65 min
November 745 77.3% 1.21% 59 min
December 769 71.5% 2.47% 64 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.