The graph describes the combination of swells directed at Tamarindo over a normal year. It is based on 20068 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the coastline so we have chosen the optimum grid node based on what we know about Tamarindo. In the case of Tamarindo, the best grid node is 28 km away (17 miles).

The rose diagram describes the distribution of swell sizes and directions, 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 were forecast only 98% of the time. Green and yellow show increasing swell sizes and red represents the highest swells, greater than >3m (>10ft). In either graph, the area of any colour is proportional to how often that size swell happens.

The diagram indicates that the most common swell direction, shown by the largest spokes, was W, whereas the the dominant wind blows from the NE. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Tamarindo and offshore. We lump these in with the no surf category of the bar chart. To avoid confusion we don't show these in the rose diagram. Because wind determines whether or not waves are good for surfing at Tamarindo, you can select a similar diagram that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. During a typical year, swells large enough to cause clean enough to surf waves at Tamarindo run for about 2.0% of the time.

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.