An aerial view of the coastal line of Riyue Bay, Wanning. [Photo/VCG]

Hainan province has a tropical monsoon marine climate. Its main characteristics include indistinct seasonal changes, mild summers without extreme heat and winters without severe cold. The annual temperature variation is small, and the average yearly temperature is high. The island experiences a clear distinction between dry and rainy seasons — dry in winter and spring, and rainy in summer and autumn — with frequent tropical cyclones. Hainan also enjoys abundant sunlight, heat and water resources, but is prone to climate-related disasters such as strong winds, droughts and cold snaps. The annual average temperature is 24.9 C.

Sunshine
Located south of the Tropic of Cancer, Hainan receives long hours of sunshine throughout the year. Except for the central mountainous areas, where fog and clouds reduce sunshine to around 1,750 hours annually, most regions receive over 2,000 hours of sunshine, with the western and southern areas reaching 2,400–2,600 hours. Peak sunlight generally comes in July, while it is the lowest in February. Sunshine is most abundant in summer and least in winter.

Temperature
Most parts of Hainan have an annual average temperature of 24.9 C. The coldest month is January, with the central mountainous areas averaging around 16.5 C, the lowest on the island. The hottest month is usually July, with Dongfang, a county-level city in Hainan, in the west recording the highest monthly average at 29.2 C.

Rainfall
Hainan is one of the rainiest areas in the world at this latitude. It has abundant moisture and high overall precipitation, though rainfall is unevenly distributed across time and space.

The average annual rainfall is about 2,014 millimeters, with a circular spatial distribution — higher in the east than in the west, more in mountainous areas than in plains, and most abundant on southeastern mountain slopes.

The island has distinct wet and dry seasons. The rainy season typically lasts from May to October, while the dry season spans from November to the following April. The rainy season sees about 80 percent of the annual rainfall. Most areas experience over 100 days of rainfall each year, with Dongfang having the fewest (87 days) and Qiongzhong Li and Miao autonomous county the most (194 days). During the rainy season, there are about 12-22 rainy days per month, while in the dry season it drops to fewer than 10 days.