San Francisco Surf Stats
- Forecast
- Maps
- Live
- Weather State
- Spot Information
All swells
This image shows the variation of swells directed at San Francisco over a normal March. It is based on 3460 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 San Francisco. In the case of San Francisco, the best grid node is 25 km away (16 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 illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These occurred 43% of the time. Green and yellow represent 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 often that size swell occurs. The diagram indicates that the dominant swell direction, shown by the biggest spokes, was SSE, whereas the the prevailing wind blows from the E. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from San Francisco and offshore. We combine these with the no surf category of the bar chart. To avoid confusion we don't show these in the rose graph. Because wind determines whether or not waves are surfable at San Francisco, you can load a different image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. During a typical March, swells large enough to cause good for surfing waves at San Francisco run for about 57% of the time.