The rose diagram shows only the swells directed at Old Orchard Beach that coincided with light winds or offshore conditions through a typical northern hemisphere spring. It is based on 5140 predictions, one every 3 hours. The direction of the spokes show where quality surf generating swell comes from. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. Green and yellow represent increasing swell sizes and highest swells greater than >3m (>10ft) are shown in red. In either graph, the area of any colour is proportional to how commonly that size swell happens.

The diagram implies that the dominant swell direction, shown by the biggest spokes, was ESE, whereas the the dominant 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 15% of the time, equivalent to 14 days. Open sea swells exceeding >3m (>10ft) are unlikely to arise in a normal northern hemisphere spring but 3% of the time you can expect swell in the range 1.3-2m (4-6.5ft) 3%, equivalent to (3 days). Taking into account the ratio of these swells that coincided with expected offshore winds, and given the fact that Old Orchard Beach is exposed to open water swells, we think that that clean surf can be found at Old Orchard Beach about 15% of the time and that surf is blown out by onshore wind 32% of the time. This is means that we expect 43 days with waves in a typical northern hemisphere spring, of which 14 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.