Predicting Tides
There are two high tides and two low tides per lunar day. A lunar day, also known as a tidal day, is measured from the time the Moon is on the meridian of an observer to the next time the Moon is on that meridian. Lunar days are 24 hours and 50 minutes, compared to solar days which are only 24 hours. A solar day is measured from the time the Sun is on that meridian of an observer to the next time the Sun is on that meridian. There are six lunar hours between high and low tides. The most accurate tidal predictions usually exist for places located on the coast because they are less effected by winds and other meteorological events.