Best time to fly Newark to San Antonio

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

Best month

September

92.1% on time · 115 flights

Worst month

June

75.6% on time · 91 flights

Month Flights On time Cancelled When late, by
January 71 84.3% 1.41% 57 min
February 82 89.6% 4.88% 66 min
March 109 86.2% 0% 65 min
April 83 89.2% 0% 38 min
May 92 83.7% 0% 65 min
June 91 75.6% 1.1% 80 min
July 117 76.3% 1.71% 128 min
August 115 78.8% 1.74% 69 min
September 115 92.1% 0.87% 52 min
October 133 84.2% 0% 45 min
November 110 90.9% 0% 32 min
December 117 83.6% 0.85% 47 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.