This image illustrates how often and how strongly the wind blows from different directions over a normal northern hemisphere spring. The longest spokes point in the directions the wind most commonly blows from and the shade of blue suggests the strength, with deep blue showing the strongest winds. It is based on 4858 NWW3 forecasts of wind since since 2007, at 3hr intervals, for the closest NWW3 model node to San Onofre, located 41 km away (25 miles). There are too few 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 most common wind at San Onofre blows from the SW. If the rose graph shows a fairly circular pattern, it means there is no strong bias in wind direction at San Onofre. Converseley, dominant spokes show favoured directions, and the more deep 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 (light blue) about 44% of the time (40 days each northern hemisphere spring) and blows offshore 48% of the time (44 days in an average northern hemisphere spring). Over an average northern hemisphere spring winds exceeding >40kph (25mph) are not expected, but 2 have winds on the range 30-40 (19-25) at San Onofre
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.