This chart describes how commonly and how strongly the wind blows from different directions through a typical June. The longest spokes point in the directions the wind most commonly blows from and the shade of blue indicates the strength, with the darkest shade of blue strongest. It is based on 1594 NWW3 forecasts of wind since since 2006, at 3hr intervals, for the closest NWW3 model node to Portreath Harbour Wall, 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 dominant wind at Portreath Harbour Wall blows from the WNW. If the rose plot shows a nearly round shape, it means there is no strong bias in wind direction at Portreath Harbour Wall. 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 June, the model suggests that winds are light enough for the sea to be glassy (light blue) about 8% of the time (2 days each June) and blows offshore 19% of the time (2 days in an average June). During a typical June wind stronger than >40kph (25mph) was forecast for only a single days at Portreath Harbour Wall
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.