The figure describes how often and how strongly the wind blows from different directions through a typical September. The longest spokes point in the directions the wind most commonly blows from and the shade of blue indicates the strength, with dark blue strongest. It is based on 1679 NWW3 forecasts of wind since since 2006, at 3hr intervals, for the closest NWW3 model node to Playa de Tres Piedras, located 22 km away (14 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 Playa de Tres Piedras blows from the W. If the rose plot shows a nearly round shape, it means there is no strong bias in wind direction at Playa de Tres Piedras. Converseley, 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 September, the model suggests that winds are light enough for the sea to be glassy (light blue) about 18% of the time (5 days each September) and blows offshore 35% of the time (6 days in an average September). During a typical September winds exceeding >40kph (25mph) are not expected, but 1 have winds on the range 30-40 (19-25) at Playa de Tres Piedras
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.