Aberaeron Swell Statistics, October: All Swell – Any Wind
The graph shows the variation of swells directed at Aberaeron through a typical October. It is based on 2480 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the shore so we have chosen the optimum grid node based on what we know about Aberaeron. In the case of Aberaeron, the best grid node is 32 km away (20 miles).
The rose diagram illustrates the distribution of swell directions and swell sizes, 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 were forecast 33% of the time. Green and yellow represent increasing swell sizes and red represents the biggest swells, greater than >3m (>10ft). In either graph, the area of any colour is proportional to how often that size swell was forecast.
The diagram indicates that the prevailing swell direction, shown by the biggest spokes, was SW, whereas the the prevailing wind blows from the SSW. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Aberaeron 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 good for surfing at Aberaeron, you can select a similar diagram that shows only the swells that were expected to coincide with glassy or offshore wind conditions. Over an average October, swells large enough to cause clean enough to surf waves at Aberaeron run for about 28% 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.