Miramar Swell Statistics, Autumn: All Swell – Any Wind
The graph illustrates the combination of swells directed at Miramar through a typical northern hemisphere autumn and is based upon 5632 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind or surf right at the coastline so we have chosen the best grid node based on what we know about Miramar. In the case of Miramar, the best grid node is 48 km away (30 miles).
The rose diagram shows 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 occurred only 36% of the time. Green and yellow illustrate increasing swell sizes and red shows largest swells greater than >3m (>10ft). In either graph, the area of any colour is proportional to how commonly that size swell happens.
The diagram implies that the prevailing swell direction, shown by the largest spokes, was W, whereas the the most common wind blows from the WNW. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Miramar and away from the coast. We group these with the no surf category of the bar chart. To avoid confusion we don't show these in the rose graph. Because wind determines whether or not waves are surfable at Miramar, you can load a different image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. Over an average northern hemisphere autumn, swells large enough to cause good for surfing waves at Miramar run for about 8% 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.