Sunset Cliffs Swell Statistics, March: All Swell – Any Wind
This chart illustrates the range of swells directed at Sunset Cliffs through a typical March and is based upon 2220 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind or surf right at the shore so we have chosen the best grid node based on what we know about Sunset Cliffs. 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 show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These occurred only 39% of the time. Green and yellow show increasing swell sizes and red illustrates largest swells greater than >3m (>10ft). In each graph, the area of any colour is proportional to how frequently that size swell happens.
The diagram suggests that the prevailing swell direction, shown by the largest spokes, was WSW, 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 Sunset Cliffs and out to sea. We lump these in 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 good for surfing at Sunset Cliffs, you can view an alternative image that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. Over an average March, swells large enough to cause clean enough to surf waves at Sunset Cliffs run for about 61% 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.