The rose diagram describes how commonly and how strongly the wind blows from different directions over a normal northern hemisphere spring. The largest spokes point in the directions the wind most commonly blows from and the shade of blue implies the strength, with the darkest shade of blue showing the strongest winds. It is based on 5140 NWW3 forecasts of wind since since 2007, at 3hr intervals, for the closest NWW3 model node to Number Threes, located 35 km away (22 miles). There are insufficient 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 Number Threes blows from the S. If the rose diagram shows a close to circular outline, it means there is no strong bias in wind direction at Number Threes. On the other hand, 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. During a typical northern hemisphere spring, the model suggests that winds are light enough for the sea to be glassy (pale blue) about 9% of the time (8 days each northern hemisphere spring) and blows offshore 14% of the time (13 days in an average northern hemisphere spring). Over an average northern hemisphere spring winds exceeding >40kph (25mph) are not expected, but 5 have winds on the range 30-40 (19-25) at Number Threes
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.