Numerical investigations dedicated to the impact of wave power variability on energy conversion were mainly conducted in the European shelf seas where a considerable amount of technological devices was developed. We complemented these studies by exploiting a 31-year consistent hindcast database of the wave climate, assessed against observations in 41 locations, in the North-West Atlantic, the Gulf of Mexico and the Caribbean Sea. With an exception in the Caribbean Sea where wave power density increased under the influence of an easterly zonal wind, a clear contrast was exhibited in the available wave energy flux between the oceanic energetic regions of the North-West Atlantic and the semi-enclosed basins, protected from incoming waves conditions by a series of islands. The analysis revealed furthermore contrasting wave climates characterized by (i) significant temporal variability in the Gulf of Mexico and the northern oceanic region off the USA East Coast, and (ii) more moderated variations in the Caribbean Sea off Colombia and the southern oceanic area off the Lesser Antilles. A generic method, independent from the device technology, was finally adopted to assess the effects of resource variability on energy output and converters performances. The area off the Lesser Antilles appeared particularly interesting to supply, at reduced installed capacity but with more regular waves conditions, renewable energy within surrounding island territories.