Grumari Surf Stats

This image shows the variation of swells directed at Grumari through an average November. It is based on 3347 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 best grid node based on what we know about Grumari. In the case of Grumari, the best grid node is 54 km away (34 miles). The rose diagram illustrates the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing but lacks 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 43% of the time. Green and yellow represent increasing swell sizes and red represents the biggest swells, greater than >3m (>10ft). In both graphs, 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 biggest spokes, was S, whereas the the prevailing wind blows from the ESE. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Grumari 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 good for surfing at Grumari, you can select a similar diagram that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. In a typical November, swells large enough to cause clean enough to surf waves at Grumari run for about 57% of the time.

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