The graph shows how commonly and how strongly the wind blows from different directions through a typical June. The largest spokes point in the directions the wind most commonly blows from and the shade of blue suggests the strength, with the darkest shade of blue showing the strongest winds. It is based on 1594 NWW3 forecasts of wind since since 2006, at 3hr intervals, for the closest NWW3 model node to Treasure Island, located 22 km away (14 miles). There are too few recording stations world wide to use actual wind data. Without question some coastal places have very localized wind effects that would not be predicted by NWW3.
According to the model, the dominant wind at Treasure Island blows from the SSW. If the rose plot shows a nearly round shape, it means there is no strong bias in wind direction at Treasure Island. Converseley, dominant spokes represent favoured directions, and the more the darkest shade of blue, the stronger the wind. Spokes point in the direction the wind blows from. Over an average June, the model suggests that winds are light enough for the sea to be glassy (the lightest shade of blue) about 51% of the time (15 days each June) and blows offshore 61% of the time (3 days in an average June). During a typical June winds exceeding >40kph (25mph) are not expected, but 0 have winds on the range 30-40 (19-25) at Treasure Island
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.