Santa Maria - Anjos Swell Statistics, Janeiro: All Swell – Any Wind
This picture illustrates the combination of swells directed at Santa Maria - Anjos through a typical January. It is based on 2372 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 Santa Maria - Anjos. In this particular case the best grid node is 14 km away (9 miles).
The rose diagram illustrates 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 occurred only 14% of the time. Green and yellow illustrate increasing swell sizes and red represents the largest 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 NW, whereas the the most common wind blows from the WSW. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Santa Maria - Anjos and away from the coast. We combine 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 Santa Maria - Anjos, you can select a similar diagram that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. Over an average January, swells large enough to cause good for surfing waves at Santa Maria - Anjos run for about 86% 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.