The graph shows how commonly and how strongly the wind blows from different directions over a normal December. The largest spokes point in the directions the wind most commonly blows from and the shade of blue suggests the strength, with the strongest winds shown by deep blue. It is based on 1736 NWW3 forecasts of wind since since 2006, at 3hr intervals, for the closest NWW3 model node to Bridgetown Harbour, located 17 km away (11 miles). There are not enough recording stations world wide to use actual wind data. No doubt some coastal places have very localized wind effects that would not be predicted by NWW3.
According to the model, the most common wind at Bridgetown Harbour blows from the NNE. If the rose diagram shows a close to circular outline, it means there is no strong bias in wind direction at Bridgetown Harbour. Converseley, dominant spokes show favoured directions, and the more deep blue, the stronger the wind. Spokes point in the direction the wind blows from. During a typical December, the model suggests that winds are light enough for the sea to be glassy (light blue) about 0.7% of the time (0 days each December) and blows offshore just 41% of the time (7 days in an average December). Over an average December winds exceeding >40kph (25mph) are not expected, but 2 have winds on the range 30-40 (19-25) at Bridgetown Harbour
IMPORTANT: Beta version feature! Swell heights are open water values from NWW3. There is no attempt to model near-shore effects. Coastal wave heights will generally be less, especially if the break does not have unobstructed exposure to the open ocean.