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

Overall: 3.2

See all 18 ratings

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Surf Report Feed

Zanzibar Swell Statistics, May: All Swell – Any Wind

The figure shows the combination of swells directed at Zanzibar over a normal May, based on 2696 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast surf and wind right at the coastline so we have chosen the best grid node based on what we know about Zanzibar, and at Zanzibar the best grid node is 35 km away (22 miles).

The rose diagram illustrates the distribution of swell sizes and directions, while the graph at the bottom shows the same thing without direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These were forecast only 92% of the time. Green and yellow illustrate increasing swell sizes and red shows biggest swells greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how frequently that size swell was forecast.

The diagram suggests that the prevailing swell direction, shown by the largest spokes, was N, whereas the the prevailing wind blows from the E. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Zanzibar and out to sea. We group these with the no surf category of the bar chart. To simplify things we don't show these in the rose plot. Because wind determines whether or not waves are surfable at Zanzibar, you can select a similar diagram that shows only the swells that were expected to coincide with glassy or offshore wind conditions. During a typical May, swells large enough to cause good for surfing waves at Zanzibar run for about 0% 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.