The rose diagram shows only the swells directed at Red Bluff that coincided with light winds or offshore conditions over a normal August. It is based on 1736 predictions, one every 3 hours. The direction of the spokes show where quality surf generating swell comes from. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. Green and yellow illustrate increasing swell sizes and biggest swells greater than >3m (>10ft) are shown in red. In either graph, 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 longest spokes, was SE, whereas the the prevailing wind blows from the WNW. The chart at the bottom shows the same thing but without direction information. For example, swells larger than 1.5 feet (0.5m) coincided with good wind conditions 25% of the time, equivalent to 8 days. Open sea swells exceeding >3m (>10ft) are unlikely to arise in a normal August. Taking into account the fraction of these swells that coincided with predicted offshore winds, and given the fact that Red Bluff is exposed to open water swells, we calculate that clean surf can be found at Red Bluff about 25% of the time and that surf is spoilt by onshore wind 26% of the time. This is means that we expect 16 days with waves in a typical August, of which 8 days should be surfable.
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.