This picture describes the variation of swells directed at Mzimpuni through an average December. It is based on 1736 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 Mzimpuni. In this particular case the best grid node is 26 km away (16 miles).

The rose diagram describes the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing but lacks 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 51% of the time. Green and yellow show increasing swell sizes and red represents highest swells greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how frequently that size swell happens.

The diagram suggests that the prevailing swell direction, shown by the largest spokes, was S, whereas the the dominant wind blows from the ESE. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Mzimpuni and offshore. We group these with the no surf category of the bar chart. To keep it simple we don't show these in the rose diagram. Because wind determines whether or not waves are clean enough to surf at Mzimpuni, 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 December, swells large enough to cause surfable waves at Mzimpuni run for about 49% 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.