Tide Graph uses the harmonic predictions from thousands of US coastal stations and presents them in a fun and interactive graph. It also includes water currents and sun/moon information. NOT FOR NAVIGATIONAL PURPOSES. USE AT YOUR OWN RISK. Tides have a great influence on the lives of boaters, fishermen, surfers, coastal communities, marine life, and vacationers just to name a few. Directly or indirectly, the great flow of our massive ocean bodies of water impact the daily lives of everyone on this planet. The cyclical movement of the Earth's tides are caused by a combination of the gravitational forces of the sun and moon as well as the shape of the costal region. Unlike simple tide clocks that you can buy in novelty stores, more accurate tide predictions use special data gathered by instruments located at each tide station. The data from these measurements are used to determine the harmonic components which then feed into the mathematical algorithms which predict tides for the future. The end results are tested for accuracy and adjustments are made as necessary. Tide Graph has US owned Tide Stations Only. An internet connection is required to get the latest tide graph. - See TideGraph.com for a complete list of stations.