The Yellow Sea (or Hwang Hai) is the name given to the northern part of the East China Sea, which is a marginal sea of the Pacific Ocean. It is located between mainland China and the Korean Peninsula. Its name comes from the sand particles from Gobi Desert sand storms that turn the surface of the water golden yellow. The sea bottom and shores are dominated by sand and silt brought by the rivers through the Bohai Sea (Liao River, Yellow River, Hai He) and the Korea Bay (Yalu River). Those deposits, together with sand storms are responsible for the yellow water color.
International Hydrographic Organization Definition
The limits of the Yellow Sea are as follows: On the South. The parallel of 33°17' North from Saisyu To (Quelpart) [now known as Jeju-do] to the mainland [of China]. On the Southeast. From the Western extreme of Quelpart to Ka Nyo or West Pinnacle Island (34°13'N) in the Mengoru Group, thence to the North point of Oku To (34°22'N), to the West point of Small South Stone Island (Syo-Zyonan To) and the North point of Great South Stone Island (Zyonan To) (34°24'N) to a point on the coast of Tin To (34°25'N) along the Northwest coast of this island to the North point thereof, and thence on a line in a Northeasterly direction to the mainland of Tyosen (Korea).
The area has cold, dry winters with strong northerly monsoons blowing from late November to March. Average January temperatures are −10 °C (14 °F) in the north and 3 °C (37 °F) in the south. Summers are wet and warm with frequent typhoons between June and October. Air temperatures range between 10 and 28 °C (50 and 82 °F). The water temperature is close to freezing in the northern part in winter, so drift ice patches and continuous ice fields form and hinder navigation between November and March. The southern waters are warmer at 6–8 °C (43–46 °F). In spring and summer, the upper layer is warmed up by the sun and diluted by the fresh water from rivers, while the deeper water remains cold and saline. Summer temperatures range between 22 and 28 °C (72 and 82 °F). Water transparency increases from about 10 meters (33 ft) in the north up to 45 meters (148 ft) in the south.