Source: accuracy: We use the best tide data available. For many places (Pacific Islands, USA, and Carribean), the tide data comes directly from the Government agencies and may therefore be relied upon to be computed from the most recent constituents. Some other websites use data of questionable accuracy and do not get updated in a timely manner.

The quality of information varies between places. For some places we have no height information, so we draw the graph using the heights for the nearest standard port. The times for high and low tides will generally be quite accurate but the true heights of the tides may vary from those shown on the graph. Heights that are shown in this way will be preceded by a tilde character (eg ~ 1.3 ft or ~ 0.7 m).