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St Ives Harbour Wall ratings
Quality on a good day: 3.0
Consistency of Surf: 2.0
Difficulty Level: 1.0
Crowds: 4.0

Overall: 3.0

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Surf Report Feed

St Ives Harbour Wall Swell Statistics, August: All Swell – Any Wind

The rose diagram describes the combination of swells directed at St Ives Harbour Wall through an average August, based on 2976 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the coastline so we have chosen the optimum grid node based on what we know about St Ives Harbour Wall. In this particular case the best grid node is 32 km away (20 miles).

The rose diagram describes the distribution of swell sizes and directions, 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 happened only 6% of the time. Green and yellow represent increasing swell sizes and red shows highest swells greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how commonly that size swell occurs.

The diagram implies that the prevailing swell direction, shown by the largest spokes, was W (which was the same as the dominant wind direction). Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from St Ives Harbour Wall and offshore. We lump these in with the no surf category of the bar chart. To simplify things we don't show these in the rose diagram. Because wind determines whether or not waves are clean enough to surf at St Ives Harbour Wall, you can view an alternative image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. In a typical August, swells large enough to cause surfable waves at St Ives Harbour Wall run for about 18% 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.