Swimming Pools Swell Statistics, Spring: All Swell – Any Wind
The graph shows the combination of swells directed at Swimming Pools through a typical northern hemisphere spring, based on 6580 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind or surf right at the coastline so we have chosen the optimum grid node based on what we know about Swimming Pools. In the case of Swimming Pools, the best grid node is 64 km away (40 miles).
The rose diagram illustrates the distribution of swell sizes and directions, while the graph at the bottom shows the same thing without direction information. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These were forecast only 88% of the time. Green and yellow illustrate increasing swell sizes and biggest swells greater than >3m (>10ft) are shown in red. In both graphs, the area of any colour is proportional to how often that size swell happens.
The diagram indicates that the prevailing swell direction, shown by the largest spokes, was W, whereas the the prevailing wind blows from the NNW. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Swimming Pools and away from the coast. 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 Swimming Pools, 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 northern hemisphere spring, swells large enough to cause surfable waves at Swimming Pools run for about 7% 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.