Swimming Pools Swell Statistics, Spring: All Swell – Any Wind
This chart illustrates the variation of swells directed at Swimming Pools through an average northern hemisphere spring, based on 5140 NWW3 model predictions since 2007 (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 Swimming Pools. In the case of Swimming Pools, the best grid node is 64 km away (40 miles).
The rose diagram describes the distribution of swell sizes and swell direction, 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 occurred only 89% of the time. Green and yellow represent increasing swell sizes and red represents largest swells greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how commonly that size swell occurs.
The diagram implies that the dominant swell direction, shown by the biggest spokes, was W, whereas the the most common wind blows from the NNW. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Swimming Pools and offshore. We lump these in with the no surf category of the bar chart. To keep it simple we don't show these in the rose diagram. 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 expected to coincide with glassy or offshore wind conditions. In a typical 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.