http://www.bahamas-travel.org/grand-bahamas-island-weather/
Weather in the Bahamas?
How common is that the bad weather in July in Grand Bahama Island?
On average, the Bahamas Islands 17 rain days in July. It is the fourth month in total rainfall, but keep in mind that the rain could be seven consecutive days followed by a storm sun for seven days. And some of the rain is short. Also on average, in July in the Caribbean has two tropical storms each year and one becomes a hurricane every two years. Always run the risk of tropical storms or hurricanes (which begin as tropical storms) when you visit most places in the Caribbean. We've been there half dozen times during the hurricane season and have never experienced a storm or hurricane. We're probably reaching the point of being lucky. All of which means that of what you have to be in the Caribbean during the particular week when a storm and if you have to be in the path of the storm as it passes. Your chances of facing a less than 50% and slightly greater than zero. FYI, your chances improve if you take a cruise ship may steer away from the storm.
GBTV: Bahamas PM tours tornado-damaged areas of Grand Bahama [03/30/10]