This picture illustrates how commonly and how strongly the wind blows from different directions through a typical southern hemisphere winter. The biggest spokes point in the directions the wind most commonly blows from and the shade of blue indicates the strength, with dark blue strongest. It is based on 5066 NWW3 forecasts of wind since since 2006, at 3hr intervals, for the closest NWW3 model node to South Beach (Wanganui), located 44 km away (27 miles). There are too few recording stations world wide to use actual wind data. Invevitably some coastal places have very localized wind effects that would not be predicted by NWW3.
According to the model, the dominant wind at South Beach (Wanganui) blows from the W. If the rose plot shows a nearly round shape, it means there is no strong bias in wind direction at South Beach (Wanganui). Converseley, dominant spokes show favoured directions, and the more deep blue, the stronger the wind. Spokes point in the direction the wind blows from. Over an average southern hemisphere winter, the model suggests that winds are light enough for the sea to be glassy (the lightest shade of blue) about 8% of the time (7 days each southern hemisphere winter) and blows offshore 23% of the time (5 days in an average southern hemisphere winter). In a typical southern hemisphere winter winds stronger than >40kph (25mph) are expected on 15 days at South Beach (Wanganui)
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.