The figure describes how often and how strongly the wind blows from different directions through a typical April. The biggest 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 1358 NWW3 forecasts of wind since since 2008, at 3hr intervals, for the closest NWW3 model node to Llandudno, located 23 km away (14 miles). There are insufficient 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 Llandudno blows from the W. If the rose graph shows a fairly circular pattern, it means there is no strong bias in wind direction at Llandudno. 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 April, the model suggests that winds are light enough for the sea to be glassy (pale blue) about 8% of the time (2 days each April) and blows offshore 35% of the time (1 days in an average April). During a typical April wind stronger than >40kph (25mph) was predicted for only a single days at Llandudno
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.