The Caribbean is a popular destination at all times of the year, but October isn’t the busiest month so it’s not something to be concerned about. The high season is generally around the same time as school holidays and more over the winter, meaning September to December is a good time to visit.
However October does fall into the hurricane season which does mean rainfall is likely, not that it will remain and the sun will soon clear it up. This can also affect your itinerary. If you want to see the best of the Caribbean without the major crowds then October is one of the best times to visit but if you’re travelling with family, more activities will be available during the peak months of February-April and July-August.