The figure describes how frequently and how strongly the wind blows from different directions through a typical year. The longest 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 20068 NWW3 forecasts of wind since since 2006, at 3hr intervals, for the closest NWW3 model node to Vila Nova de Milfontes, located 30 km away (19 miles). There are not enough 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 prevailing wind at Vila Nova de Milfontes 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 Vila Nova de Milfontes. On the other hand, dominant spokes illustrate favoured directions, and the more deep blue, the stronger the wind. Spokes point in the direction the wind blows from. Over an average year, the model suggests that winds are light enough for the sea to be glassy (light blue) about 1.4% of the time (5 days each year) and blows offshore just 3% of the time (11 days in an average year). In a typical year winds stronger than >40kph (25mph) are expected on 5 days at Vila Nova de Milfontes
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.