Best time to fly San Juan to Charlotte Amalie

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

Best month

May

93.5% on time · 62 flights

Worst month

February

60% on time · 56 flights

Month Flights On time Cancelled When late, by
January 62 62.3% 1.61% 61 min
February 56 60% 0% 70 min
March 62 83.9% 0% 39 min
April 60 83.3% 0% 37 min
May 62 93.5% 0% 50 min
June 60 68.3% 0% 38 min
July 101 76.2% 0% 95 min
August 99 72.9% 2.02% 96 min
September 71 72.9% 1.41% 72 min
October 81 77.8% 0% 67 min
November 60 76.7% 0% 67 min
December 62 72.6% 0% 52 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.