Tarnos - La Digue Swell Statistics, May: All Swell – Any Wind
The rose diagram describes the combination of swells directed at Tarnos - La Digue through an average May, based on 1736 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 most applicable grid node based on what we know about Tarnos - La Digue. In this particular case 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 without 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 were forecast only 11% of the time. Green and yellow show increasing swell sizes and red illustrates the highest swells, greater than >3m (>10ft). In either graph, the area of any colour is proportional to how commonly that size swell was forecast.
The diagram implies that the prevailing swell direction, shown by the largest spokes, was WNW (which was the same as the dominant wind direction). 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 surfable 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. In a typical May, swells large enough to cause good for surfing waves at Tarnos - La Digue run for about 89% 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.