In addition to astronomical causes of tidal fluctuations, terrestrial factors also exist which produce variations in the level of sea like:
* tectonic movements of the terrestrial crust,
* variations in the atmospheric pressure,
* water piling up or retirement by wind that blows towards or from the coast,
* heating of waters by phenomena like El Nino and global warming.

The tide ranks (difference between the high water and low tide) are very different for both coasts of Costa Rica, whose difference has to do with the marine bottom and the form in which the tide in both ocean basins oscillates. The tide rank average in our Pacific Coast is of 2,80 meters and in the Caribbean of 0,30 meters.