I've recently been converted to this windsurfing site http://www.windguru.com/int/index.php?sc=47904
(the link shows Ventnor) - which is currently showing a number of different wind speeds and wave heights (depending upon the forecast model chosen) at 13:00 tomorrow :-
Wind Gust Wave Height
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It's the wave height, period and direction that I have found to be the most useful (and accurate every time up to about 2 days ahead) rather than the wind speed when planning an outing.