Mitchell's Cove Swell Statistics, Summer: All Swell – Any Wind
This image shows the range of swells directed at Mitchell's Cove through an average northern hemisphere summer, based on 5802 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind or surf right at the coastline so we have chosen the best grid node based on what we know about Mitchell's Cove. In this particular case the best grid node is 42 km away (26 miles).
The rose diagram describes the distribution of swell sizes and swell direction, 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 were forecast only 35% of the time. Green and yellow illustrate increasing swell sizes and biggest swells greater than >3m (>10ft) are shown in red. In both graphs, 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 WNW (which was the same as the prevailing wind direction). Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Mitchell's Cove and out to sea. We lump these in with the no surf category of the bar chart. To avoid confusion we don't show these in the rose diagram. Because wind determines whether or not waves are good for surfing at Mitchell's Cove, you can load a different image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. In a typical northern hemisphere summer, swells large enough to cause clean enough to surf waves at Mitchell's Cove run for about 31% 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.