Calculation of High and Low Tides in Xiamen

Tides are the periodic rise and fall of seawater subject to the attraction of the moon and the sun. There are two types of tides, i.e. half-day tide (two rise-and-fall cycles within one day) and full-day tide (only one rise-and-fall cycle within one day). Xiamen is characterized by half-day tides.

A simple way to calculate the high and low tides at Xiamen is as follows: the high tide of the 1st and 16th days of a month on a lunar calendar takes place at 0:00 and 12:00 sharp and the low tide takes place at 6:00 and 18:00 sharp. They are collectively referred to as the datum point for tide calculation. The high and low tides of other days of the month = datum point + lunar calendar date x 0.8.

For instance, in case of the 5th day of the month, high tide time = 0 + 5×0.8 and 12 + 5×0.8, i.e. the high tide of the 5th day of the month on a lunar calendar takes place at 4:00 and 16:00 sharp while the low tide takes place at 10:00 and 22:00 sharp. The best period for swimming: tidal currents may also occur with the rise and fall of tides. Tidal currents flow towards the coast during the flood tide but back from the beaches during ebb tide.

For that reason, the best period for swimming is from 3 hours before high tide until high tide. You may easily get injured by oyster shells on the seabed during low tide. Meanwhile, the ebbing current that occurs during ebb tide may carry you out to sea and place you in grave danger.