It depends on where you want to go. The best months to visit the islands are May, June, early July, September and early October. 

Normally sailing yacht charters begin and end on Saturdays. The normal duration of a charter is for one week, ore multiples of weeks. Of course, whenever possible Aegean Yachts will try to accommodate your needs to start and end on different days of the week, and also for uneven periods of time such as a five or eleven-day charter.

You should be able to recoup any payments through your holiday cancellation insurance. Cancellation policy is governed by the terms of the hellastrek tour or any other services contract. It might be possible to waive cancellation costs altogether if the cancelled tour is re-book for the same duration, under the same conditions.