St John is the place for beautiful beaches.
Hurricane season is technically from June 1st to Nov 30th.
In general the chances of getting hit by a Hurricane are almost nil.
If anything you might have a Tropical depression which may last for a day or 2 or most probably you'll have all sunshine for your stay with a daily 5 minute shower.
So enjoy <img src="http://www.traveltalkonline.com/forums/images/graemlins/toast.gif" alt="" />