Best time to fly Charlotte Amalie to San Juan

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

Best month

May

87.5% on time · 72 flights

Worst month

January

62.2% on time · 116 flights

Month Flights On time Cancelled When late, by
January 116 62.2% 4.31% 98 min
February 99 66% 5.05% 87 min
March 111 75.7% 0% 66 min
April 109 85.3% 0% 34 min
May 72 87.5% 0% 42 min
June 74 77% 0% 47 min
July 115 69.6% 0% 72 min
August 113 70% 2.65% 115 min
September 71 74.3% 1.41% 134 min
October 91 81.1% 0% 70 min
November 83 71.1% 0% 73 min
December 105 67.3% 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.