This image shows only the swells directed at Shamal Bandar that coincided with light winds or offshore conditions through a typical northern hemisphere spring. It is based on 4858 predictions, one every 3 hours. The direction of the spokes show where quality surf generating swell comes from. Five colours represent increasing wave sizes. Very small swells of less than 0.5m (1.5 feet) high are shown in blue. Green and yellow show increasing swell sizes and largest swells greater than >3m (>10ft) are shown in red. In each graph, the area of any colour is proportional to how frequently that size swell occurs.
The diagram suggests that the dominant swell direction, shown by the longest spokes, was S, whereas the the most common wind blows from the WSW. 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 34% of the time, equivalent to 31 days. Open sea swells exceeding >3m (>10ft) are unlikely to happen in a normal northern hemisphere spring but 4% of the time you can expect swell in the range 1.3-2m (4-6.5ft) 4%, equivalent to (4 days). Taking into account the fraction of these swells that coincided with expected offshore winds, and given the fact that Shamal Bandar is exposed to open water swells, we calculate that clean surf can be found at Shamal Bandar about 34% of the time and that surf is blown out by onshore wind 46% of the time. This is means that we expect 73 days with waves in a typical northern hemisphere spring, of which 31 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.