Best time to fly New York to Salt Lake City

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

Best month

August

87.7% on time · 154 flights

Worst month

December

68.7% on time · 168 flights

Month Flights On time Cancelled When late, by
January 159 69.3% 5.03% 62 min
February 174 78.8% 7.47% 79 min
March 197 78.5% 1.02% 57 min
April 162 84% 0% 53 min
May 155 83.2% 0% 83 min
June 150 72% 0% 75 min
July 155 72.7% 3.23% 84 min
August 154 87.7% 0% 67 min
September 150 84.7% 0% 60 min
October 156 80.6% 0.64% 53 min
November 148 80.3% 0.68% 51 min
December 168 68.7% 2.98% 58 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.