The graph illustrates how often and how strongly the wind blows from different directions through a typical December. The biggest spokes point in the directions the wind most commonly blows from and the shade of blue suggests the strength, with dark blue strongest. It is based on 1736 NWW3 forecasts of wind since since 2006, at 3hr intervals, for the closest NWW3 model node to Southerndown, located 26 km away (16 miles). There are not enough recording stations world wide to use actual wind data. Without question some coastal places have very localized wind effects that would not be predicted by NWW3.
According to the model, the most common wind at Southerndown blows from the WSW. If the rose diagram shows a close to circular outline, it means there is no strong bias in wind direction at Southerndown. By contrast, dominant spokes show 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 December, the model suggests that winds are light enough for the sea to be glassy (pale blue) about 6% of the time (2 days each December) and blows offshore 20% of the time (1 days in an average December). During a typical December winds stronger than >40kph (25mph) are expected on 6 days at Southerndown
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.