Ackergill Swell Statistics, June: All Swell – Any Wind
The rose diagram illustrates the combination of swells directed at Ackergill through a typical June, based on 2306 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the shore so we have chosen the optimum grid node based on what we know about Ackergill. In this particular case the best grid node is 5 km away (3 miles).
The rose diagram shows the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing without direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These happened 71% of the time. Green and yellow show increasing swell sizes and largest 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 happens.
The diagram implies that the most common swell direction, shown by the biggest spokes, was N (which was the same as the most common wind direction). Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Ackergill and out to sea. We lump these in with the no surf category of the bar chart. To keep it simple we don't show these in the rose graph. Because wind determines whether or not waves are surfable at Ackergill, you can view an alternative image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. Over an average June, swells large enough to cause good for surfing waves at Ackergill run for about 29% 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.