The rose diagram illustrates how commonly and how strongly the wind blows from different directions over a normal March. The largest spokes point in the directions the wind most commonly blows from and the shade of blue indicates the strength, with the strongest winds shown by the darkest shade of blue. It is based on 1721 NWW3 forecasts of wind since since 2007, at 3hr intervals, for the closest NWW3 model node to Kodogawa, located 33 km away (21 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 prevailing wind at Kodogawa blows from the SE. If the rose diagram shows a close to circular outline, it means there is no strong bias in wind direction at Kodogawa. On the other hand, dominant spokes represent 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 March, the model suggests that winds are light enough for the sea to be glassy (pale blue) about 9% of the time (3 days each March) and blows offshore 35% of the time (0 days in an average March). Over an average March wind stronger than >40kph (25mph) was forecast for only a single days at Kodogawa
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.