Sunset Cliffs Swell Statistics, March: All Swell – Any Wind
This picture illustrates the combination of swells directed at Sunset Cliffs through an average March, based on 1724 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast surf and wind right at the coastline so we have chosen the optimum grid node based on what we know about Sunset Cliffs. In the case of Sunset Cliffs, 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 but without direction information. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These happened only 49% of the time. Green and yellow illustrate 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 prevailing swell direction, shown by the longest 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 keep it simple we don't show these in the rose plot. Because wind determines whether or not waves are surfable at Sunset Cliffs, you can view an alternative image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. In a typical March, swells large enough to cause good for surfing waves at Sunset Cliffs run for about 51% 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.