The terrain of Hainan Island is high in the middle and low on the surrounding sides. Most of the relatively large rivers originate from the central mountainous area, forming a radial water system.

There are 154 rivers flowing into the sea alone on the island, of which 38 have water surfaces exceeding 100 square kilometers.

Nandu River, Changhua River and Wanquan River are the three major rivers in Hainan Island, and the drainage area of ??these three rivers accounts for 47% of the island's area.

The Nandu River originates from Nanfeng Mountain in Baisha County, runs diagonally across the northern part of the island, and reaches the sea in Haikou City, with a total length of 311 kilometers; the Changhua River originates from Kongshiling in Qiongzhong County, runs across the western part of Hainan Island, and enters the sea at Changhua Port, with a total length of 230 kilometers.

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The upper reaches of the Wanquan River are divided into two branches, the north and the south, which originate from Wuzhishan and Fengmenling in Qiongzhong County respectively. The two rivers merge at Hekouzui of Longjiang River in Qionghai City and enter the sea at Boao Port. The total length of the main stream is 163 kilometers.

There are few naturally formed lakes on Hainan Island and there are mostly artificial reservoirs. The famous ones include Songtao Reservoir, Niululing Reservoir, Daguangba Reservoir and Nanli Lake.

Extended information: Climate characteristics: Hainan Island is located at the northern edge of the tropics and has a tropical monsoon climate. It has always been known as a "natural greenhouse". It has long summers and no winters. The annual average temperature is 22~27℃, and the accumulated temperature greater than or equal to 10℃ is

8200℃, the temperature in the coldest January is still 17-24℃, the annual sunshine is 1750-2650 hours, the light rate is 50%-60%, the light temperature is sufficient, and the photosynthetic potential is high.

Hainan Island has early spring, rapid temperature rise, large daily temperature difference, no frost all year round, and warm winters. Rice can be harvested three times and vegetables are available all year round. It is an ideal base for breeding in southern China.

Hainan Province has abundant rainfall, with annual precipitation ranging from 1,000 mm to 2,600 mm. The average annual precipitation is 1,639 mm. There are obvious rainy seasons and less rainy seasons.

May to October every year is the rainy season, with a total precipitation of about 1,500 mm, accounting for 70 to 90% of the total annual precipitation. The main rain sources include frontal rain, thermal thunderstorms and typhoon rain, from November to April of the following year.

It is the dry season, accounting for only 10 to 30% of the annual precipitation. Drought often occurs in the dry season.