El Porto Beach Swell Statistics, January: All Swell – Any Wind
This chart shows the variation of swells directed at El Porto Beach through a typical January, based on 1925 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 best grid node based on what we know about El Porto Beach. In the case of El Porto Beach, the best grid node is 46 km away (29 miles).
The rose diagram describes 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 were forecast only 18% of the time. Green and yellow show increasing swell sizes and red represents biggest swells greater than >3m (>10ft). 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 biggest spokes, was WSW, whereas the the prevailing wind blows from the N. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from El Porto Beach and offshore. We combine these 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 good for surfing at El Porto Beach, 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 January, swells large enough to cause clean enough to surf waves at El Porto Beach run for about 82% 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.