Umzumbe Surf Stats

This chart describes the combination of swells directed at Umzumbe through a typical July and is based upon 3472 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 optimum grid node based on what we know about Umzumbe, and at Umzumbe the best grid node is 33 km away (21 miles). The rose diagram shows the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing but without 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 38% of the time. Green and yellow represent increasing swell sizes and red shows the highest swells, greater than >3m (>10ft). In either graph, the area of any colour is proportional to how often that size swell was forecast. The diagram indicates that the most common swell direction, shown by the longest spokes, was SSW, whereas the the dominant wind blows from the NW. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Umzumbe and offshore. We lump these in 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 clean enough to surf at Umzumbe, you can view an alternative image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. Over an average July, swells large enough to cause surfable waves at Umzumbe run for about 59% of the time.

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