The rose diagram illustrates how often and how strongly the wind blows from different directions through a typical April. The largest spokes point in the directions the wind most commonly blows from and the shade of blue implies the strength, with deep blue showing the strongest winds. It is based on 1638 NWW3 forecasts of wind since since 2007, at 3hr intervals, for the closest NWW3 model node to Faro de Trafalgar, located 21 km away (13 miles). There are not enough recording stations world wide to use actual wind data. Invevitably some coastal places have very localized wind effects that would not be predicted by NWW3.
According to the model, the most common wind at Faro de Trafalgar blows from the W. If the rose diagram shows a close to circular outline, it means there is no strong bias in wind direction at Faro de Trafalgar. Converseley, dominant spokes show favoured directions, and the more deep blue, the stronger the wind. Spokes point in the direction the wind blows from. Over an average April, the model suggests that winds are light enough for the sea to be glassy (the lightest shade of blue) about 7% of the time (2 days each April) and blows offshore 21% of the time (6 days in an average April). During a typical April wind stronger than >40kph (25mph) was expected for only a single days at Faro de Trafalgar
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.