The island was deserted for almost half a century. While the island is not open to the general public, the school runs a series of week-long courses there on survival and stewardship of the outdoors. In a nice bit of irony, the school uses the old quarry on the island for ropes courses, teaching rock climbing to students of all ages. Sea kayaking, small boating, and sailing are the best ways to poke around the multitude of small granite islands that fill Penobscot Bay. Hurricane Island isn't open to the general public, but Vinalhaven and North Haven are.
Weather conditions are changeable here at any time of year.
July and August are generally warm and dryish, so they are the peak months along the coast. Shoulder seasons can have decent weather as well, and the crowds are smaller then. Major airports are in Bangor and Portland. In the summer, a ferry runs six times a day from Rockland to Vinalhaven. Winter schedules vary, so call ahead.