I don't have any specific information on ST. Kitts. As far as hurricane season in general, you have a very small chance of a hurricane but September is the height of hurricane season. Many people from the north don't like traveling to the Caribbean in September because it is fairly hot and humid then. If you do decide to book in September, trip cancellation/interruption/etc. insurance is a good idea. Don't have any idea about ST. Kitts in particular, but many places in the Caribbean, many of the restaurants are closed in September. We love travelling to SXM in September, have done it many times, because we love travelling without a crowd, but St. Kitts MAY be deserted then, I don't know.