Arinaga Swell Statistics, February: All Swell – Any Wind
The rose diagram describes the variation of swells directed at Arinaga over a normal February and is based upon 2102 NWW3 model predictions since 2007 (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 Arinaga. In this particular case the best grid node is 42 km away (26 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 were forecast only 10% of the time. Green and yellow illustrate increasing swell sizes and highest swells greater than >3m (>10ft) are shown in red. In either graph, 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 NNW, whereas the the dominant wind blows from the NNE. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Arinaga and away from the coast. We group these with the no surf category of the bar chart. To keep it simple we don't show these in the rose diagram. Because wind determines whether or not waves are clean enough to surf at Arinaga, you can view an alternative image that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. During a typical February, swells large enough to cause surfable waves at Arinaga run for about 28% 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.