Tarnos - La Digue Swell Statistics, May: All Swell – Any Wind
The graph shows the combination of swells directed at Tarnos - La Digue over a normal May and is based upon 1894 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast surf and wind right at the coast so we have chosen the most applicable grid node based on what we know about Tarnos - La Digue, and at Tarnos - La Digue the best grid node is 39 km away (24 miles).
The rose diagram shows the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing but without direction information. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These were forecast only 10% 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 often that size swell occurs.
The diagram indicates that the prevailing swell direction, shown by the largest spokes, was WNW, whereas the the prevailing wind blows from the NW. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Tarnos - La Digue 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 diagram. Because wind determines whether or not waves are good for surfing at Tarnos - La Digue, 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 clean enough to surf waves at Tarnos - La Digue run for about 90% 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.