Ironwood Beach Swell Statistics, January: All Swell – Any Wind
This chart describes the variation of swells directed at Ironwood Beach through a typical January. It is based on 1728 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast surf and wind right at the coast so we have chosen the best grid node based on what we know about Ironwood Beach. In this particular case the best grid node is 17 km away (11 miles).
The rose diagram describes the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing without direction information. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These occurred only 20% of the time. Green and yellow illustrate 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 biggest spokes, was NNW, whereas the the dominant wind blows from the E. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Ironwood Beach and out to sea. We group these with the no surf category of the bar chart. To keep it simple we don't show these in the rose plot. Because wind determines whether or not waves are surfable at Ironwood Beach, you can load a different image that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. Over an average January, swells large enough to cause good for surfing waves at Ironwood Beach run for about 80% 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.