This picture describes how often and how strongly the wind blows from different directions through a typical April. The largest spokes point in the directions the wind most commonly blows from and the shade of blue implies the strength, with the strongest winds shown by dark blue. It is based on 1680 NWW3 forecasts of wind since since 2007, at 3hr intervals, for the closest NWW3 model node to Point Lonsdale, located 25 km away (16 miles). There are insufficient 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 dominant wind at Point Lonsdale blows from the SW. If the rose plot shows a nearly round shape, it means there is no strong bias in wind direction at Point Lonsdale. By contrast, dominant spokes illustrate favoured directions, and the more the darkest shade of blue, the stronger the wind. Spokes point in the direction the wind blows from. Over an average April, the model suggests that winds are light enough for the sea to be glassy (the lightest shade of blue) about 14% of the time (4 days each April) and blows offshore 34% of the time (10 days in an average April). During a typical April wind stronger than >40kph (25mph) was expected for only a single days at Point Lonsdale
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.