Pacific Beach Pier Swell Statistics, October: All Swell – Any Wind
The rose diagram illustrates the range of swells directed at Pacific Beach Pier through an average October and is based upon 1984 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast surf and wind right at the coastline so we have chosen the most applicable grid node based on what we know about Pacific Beach Pier. In this particular case the best grid node is 32 km away (20 miles).
The rose diagram describes the distribution of swell sizes and directions, while the graph at the bottom shows the same thing but lacks direction information. Five colours represent increasing wave sizes. Very small swells of less than 0.5m (1.5 feet) high are shown in blue. These occurred only 4% of the time. Green and yellow represent increasing swell sizes and red shows the largest swells, greater than >3m (>10ft). In either graph, the area of any colour is proportional to how commonly that size swell was forecast.
The diagram implies that the most common swell direction, shown by the longest spokes, was SW, whereas the the most common wind blows from the WNW. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Pacific Beach Pier and out to sea. We group these 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 surfable at Pacific Beach Pier, 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 October, swells large enough to cause good for surfing waves at Pacific Beach Pier run for about 96% 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.