(all temperatures shown in Farenheit)
Generally speaking the weather in the Bahamas is sunny and warm, with temperatures ranging from 77° to 89°, and as is typical in the Caribbean it's fairly humid. The water is delightfully warm and crystal-clear, with temps ranging from 74° in the winter months to 84° in the summer months, which makes for a very pleasant swim. Evenings are slightly cooler and sometimes breezy, so pack a light jacket or sweater.
Although it can rain in the Caribbean all year long, May through October is considered the "rainy season", during which the Bahamas will usually experience a brief afternoon downpour which clears quickly, so be sure to pack an umbrella. June through November is considered "hurricane season" during which the islands can, but do not always, experience a hurricane. To assist travelers, many Bahamas hoteliers have instituted a Hurricane Hotel Policy for vacationers which states that visitors who cancel a Bahamas vacation during a hurricane will receive an immediate refund with no penalties. If caught on-island during a hurricane, they would be extended the lowest possible rate and all possible courtesies.