Imperial Beach Surf Stats

The rose diagram illustrates the range of swells directed at Imperial Beach through a typical September. It is based on 3360 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 optimum grid node based on what we know about Imperial Beach. In the case of Imperial Beach, the best grid node is 36 km away (22 miles). The rose diagram describes the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing but 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 3% of the time. Green and yellow represent increasing swell sizes and red represents the largest swells, greater than >3m (>10ft). In either graph, the area of any colour is proportional to how often that size swell happens. The diagram indicates that the dominant swell direction, shown by the largest 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 Imperial Beach and out to sea. We group these with the no surf category of the bar chart. To avoid confusion we don't show these in the rose diagram. Because wind determines whether or not waves are good for surfing at Imperial Beach, 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 clean enough to surf waves at Imperial Beach run for about 97% of the time.

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