The average rainfall is 1,263 mm. The rainy season runs from June to October, and the rainfall often increases in the typhoon season. The rainfall of the rainy season accounts for 90.2% of the year total. Sanya is fog-free all year round. The annual average temperature is 25.5 ℃, the highest temperature occurs in June with a monthly average temperature of 28.8 ℃. The lowest temperature occurs in January with a monthly average temperature of 21.6 ℃. The extreme temperature reaches up to 35,9 ℃ and the lowest hits 5.1 ℃. There is irregular diurnal tide, mainly diurnal lasting 14 days every month. The highest tide level of 2.2 meters for 16 hours, the lowest level is 0.6 m, for an average of 1.03 meters. The maximum tidal range is 2.26 m, the minimum tidal range is 0.06 m, for an average tidal range of 0.79 m. When the tide comes, the water is divided into two tributaries, one to the southeast, via the terminal and into Sanya River at a flow rate of 0.35 m / sec; another towards northwest from the Baipaijiao gap at a flow rate 0.35 m / sec. When the ebb comes, the flow direction will reverse at a flow rate of 1.08 m / sec and 0.07 m / sec respectively. The ebb lasts 8 hours, the sediment will be brought into the sea by the ebb, leaving less sedimentation in the harbor basin.