Some say its too hot, others say, “but what about the hurricanes.” Yes, it is hot in summer, But the ocean is still beautiful. The winds are generally much lighter to even nonexistent. No wind makes sailing difficult, but either a powerboat or sailboat under power moves quite quickly when the seas are flat. There are so many fewer people out boating that this alone would be enough to draw me in. Summer is by far the best time to come if you are a scuba diver. The water is in the mid to high 80s, and the flat seas allow for exploration on more remote sites.
During September and October, the Caribbean goes into offseason mode. Many of the bars, restaurants, resorts, etc. close down completely. Many people who are in the boating industry go away on vacation, and the islands become ghost towns. I like it. Summer is not the time to come if you are going out every night to the wee hours.
Yes, they are the months that hurricanes are most likely in the islands. However, they are few and far between. We see a dozen or more every year on the news, but a particular island is not likely to feel the full effects of one for more than a couple of days every 3 or 5 years.
Yes, it could be the week you decided to go on vacation if you are super unlucky. Buy trip insurance! Insurance generally costs about 7% of your total vacation cost. However, at this time of year, the price of airfares is as low as can be, and the amount of renting a boat can be as little as 50% of that in peak season. The math looks great.