Gyllyngvase Beach Swell Statistics, May: All Swell – Any Wind
The rose diagram illustrates the range of swells directed at Gyllyngvase Beach over a normal May, based on 2200 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind or surf right at the coast so we have chosen the optimum grid node based on what we know about Gyllyngvase Beach, and at Gyllyngvase Beach the best grid node is 16 km away (10 miles).
The rose diagram illustrates the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing but 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 happened only 93% 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 frequently that size swell happens.
The diagram suggests that the dominant swell direction, shown by the biggest spokes, was SSE, whereas the the most common wind blows from the WNW. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Gyllyngvase Beach and out to sea. We group these 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 clean enough to surf at Gyllyngvase Beach, you can view an alternative image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. During a typical May, swells large enough to cause surfable waves at Gyllyngvase Beach run for about 0% 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.