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Groenvlei ratings
Quality on a good day: 3.0
Consistency of Surf: 4.0
Difficulty Level: 1.0
Crowds: 4.0

Overall: 3.3

See all 18 ratings

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Surf Report Feed

Groenvlei Swell Statistics, April: All Swell – Any Wind

The figure illustrates the variation of swells directed at Groenvlei over a normal April, based on 2880 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast surf and wind right at the shore so we have chosen the optimum grid node based on what we know about Groenvlei, and at Groenvlei the best grid node is 56 km away (35 miles).

The rose diagram shows the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing 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 were forecast only 7% of the time. Green and yellow show increasing swell sizes and red represents largest swells greater than >3m (>10ft). In either graph, the area of any colour is proportional to how frequently that size swell occurs.

The diagram suggests that the dominant swell direction, shown by the biggest spokes, was SSW, whereas the the most common wind blows from the S. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Groenvlei and away from the coast. We lump these in 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 surfable at Groenvlei, you can select a similar diagram that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. During a typical April, swells large enough to cause good for surfing waves at Groenvlei run for about 93% 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.