This picture describes how frequently and how strongly the wind blows from different directions through a typical northern hemisphere spring. The biggest spokes point in the directions the wind most commonly blows from and the shade of blue suggests the strength, with the strongest winds shown by deep blue. It is based on 3773 NWW3 forecasts of wind since since 2008, at 3hr intervals, for the closest NWW3 model node to Berck Sur Mer, located 11 km away (7 miles). There are insufficient 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 Berck Sur Mer 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 Berck Sur Mer. On the other hand, dominant spokes illustrate favoured directions, and the more dark blue, the stronger the wind. Spokes point in the direction the wind blows from. Over an average northern hemisphere spring, the model suggests that winds are light enough for the sea to be glassy (the lightest shade of blue) about 7% of the time (6 days each northern hemisphere spring) and blows offshore 14% of the time (4 days in an average northern hemisphere spring). In a typical northern hemisphere spring winds stronger than >40kph (25mph) are expected on 2 days at Berck Sur Mer
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.