Castles Swell Statistics, February: All Swell – Any Wind
This image illustrates the variation of swells directed at Castles through a typical February. It is based on 2032 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast surf and wind right at the shore so we have chosen the most applicable grid node based on what we know about Castles. In the case of Castles, the best grid node is 32 km away (20 miles).
The rose diagram illustrates the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing but without direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These occurred only 52% of the time. Green and yellow show increasing swell sizes and largest swells greater than >3m (>10ft) are shown in red. In each graph, the area of any colour is proportional to how commonly that size swell happens.
The diagram implies that the most common swell direction, shown by the longest spokes, was SE, whereas the the most common wind blows from the WNW. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Castles and away from the coast. We lump these in with the no surf category of the bar chart. To avoid confusion we don't show these in the rose plot. Because wind determines whether or not waves are clean enough to surf at Castles, you can select a similar diagram that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. Over an average February, swells large enough to cause surfable waves at Castles run for about 48% of the time.
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.