Bermuda is 650 miles east of Cape Hatteras, North Carolina and is made up of more than 130 islands, many linked by bridges and causeways. See geography . August can be humid, the winter months are similar to a warm British summer.
Visibility is less good in winter due to plankton.
No vaccinations necessary, excellent medical facilities, insurance essential. The only marine creature to avoid is the Portuguese man of war. Outside the summer months it can get cool in the evenings. All major credit cards widely accepted. BA flies three times a week from Gatwick - early booking is essential.