Wave and tide conditions are complex. Under the monsoon
background, wave directions vary from NE in winter to SE in
summer. Most incident wave directions are NE-E with the dominant
wave direction NE in winter, and SE-S in summer. Maximum
wave heights occur during the passage of typhoons during summer
and fall; however, winter storms can also generate high waves for
durations on the order of 10 days. Influenced by the coastal terrain,
the distribution of annual mean wave height and period show a
gradually decreasing trend from east to west. The annual mean
wave height from Southern Fujian to eastern Guangdong and Pear
River Estuary is 1.1e1.3 m with wave periods ranging from 3.9 to
5.1 s. Western Guangdong and eastern Hainan Island have an
annual average wave height of 0.48e1.0 m and an annual average
period of 3.5e4.2 s. The annual mean wave height along Beibu Bay
is 0.5e0.8 m with an average wave period of 3.0e3.1 s. The tidal
range along the southern Fujian and southern Guangxi coast is the
largest at 4.0e6.0 m on average. Microtidal conditions exist from
eastern Guangdong to Maomin, with an average tidal range of
1.0e2.0 m, while the tidal range on the east and west sides of
Leizhou Peninsula is about 2.0e4.0 m.