This image shows only the swells directed at Shamal Bandar that coincided with light winds or offshore conditions through a typical northern hemisphere autumn. It is based on 5144 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 represent increasing swell sizes and red shows the largest swells, greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how frequently that size swell occurs.
The diagram suggests that the most common swell direction, shown by the longest spokes, was S, whereas the the most common wind blows from the W. 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 37% of the time, equivalent to 34 days. Open sea swells exceeding >3m (>10ft) are unlikely to happen in a normal northern hemisphere autumn but 8% of the time you can expect swell in the range 1.3-2m (4-6.5ft) 8%, equivalent to (7 days). Taking into account the ratio of these swells that coincided with forecast offshore winds, and given the fact that Shamal Bandar is exposed to open water swells, we estimate that clean surf can be found at Shamal Bandar about 37% of the time and that surf is messed up by onshore wind 34% of the time. This is means that we expect 65 days with waves in a typical northern hemisphere autumn, of which 34 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.