The forecast data
Swellcast is based on the same freely available data as the majority of other surf forecast services, namely the National Oceanic & Atmospheric Administration's Wave Watch III model.
We fetch new data every six hours, and for some locations run our own minor adjustments. A major difference between swellcast and some other forecast services is that we have chosen not to extrapolate the data down to individual surf spots. The data we publish is for broader open ocean areas, designed to complement local knowledge and leave the decision making up to you.
The live wind readings
We fetch most live wind readings every 30 minutes from the Australian Bureau of Meteorology. We've chosen the most relevant live wind stations available for each swellcast location.
The forecast watch feature
The forecast watch is designed to enhance the forecast graphs, giving you the ability to highlight days/times that meet your desired criteria. Watch criteria are completely flexible, which means you can define any combination of swell height, period and direction, and wind speed and direction. This feature was lauched in September 2013.
At this stage we are generating custom geo-visualisation of swell height for the oceanic region. This feature was added in September 2013, and will gradually be expanded to cover swell period and direction, and wind parameters. We will also be introducing animated maps in the near future.