You can calibrate our breaking wave estimates in two ways: If the forecast is consistently over or under-calling the waves then use the 'wave height modifier' to adjust the scale. If the forecast is getting things wrong for particular swell directions then try adjusting the 'optimum swell direction'. Trial and error coupled with local knowledge will let you fine tune things where there are problems - although be aware some subtle local factors like a blocking headland, a deep water channel and tidal currents etc. will get missed. The breaking wave estimate is only ever a guide to using our detailed swell data to make the final call.