Huntington Pier Swell Statistics, September: All Swell – Any Wind
The figure shows the combination of swells directed at Huntington Pier through a typical September and is based upon 2160 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the coast so we have chosen the best grid node based on what we know about Huntington Pier. In this particular case the best grid node is 19 km away (12 miles).
The rose diagram describes 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 occurred only 29% of the time. Green and yellow illustrate increasing swell sizes and red shows the biggest swells, greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how frequently that size swell was forecast.
The diagram suggests that the dominant swell direction, shown by the longest spokes, was SW, whereas the the prevailing wind blows from the WSW. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Huntington Pier and out to sea. We lump these in with the no surf category of the bar chart. To simplify things we don't show these in the rose graph. Because wind determines whether or not waves are clean enough to surf at Huntington Pier, you can view an alternative image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. Over an average September, swells large enough to cause surfable waves at Huntington Pier run for about 1.0% 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.