Aberystwyth harbour trap Swell Statistics, February: All Swell – Any Wind
The figure illustrates the range of swells directed at Aberystwyth harbour trap through an average February, based on 2101 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind or surf right at the shore so we have chosen the optimum grid node based on what we know about Aberystwyth harbour trap, and at Aberystwyth harbour trap the best grid node is 29 km away (18 miles).
The rose diagram describes the distribution of swell sizes and directions, while the graph at the bottom shows the same thing but without direction information. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These happened 36% 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 frequently that size swell was forecast.
The diagram suggests that the prevailing swell direction, shown by the largest spokes, was SW (which was the same as the most common wind direction). Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Aberystwyth harbour trap and offshore. We combine these with the no surf category of the bar chart. To keep it simple we don't show these in the rose plot. Because wind determines whether or not waves are clean enough to surf at Aberystwyth harbour trap, you can view an alternative image that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. In a typical February, swells large enough to cause surfable waves at Aberystwyth harbour trap run for about 34% 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.