The cultivation farms are mainly located in Hainan province. Hainan province is in the extreme south of China. The difference in temperature between the summer and the winter is small. The average temperature is high. The sunshine hour is 1780-2600 hours per year. The solar radiation is 4500-5800 megajoule per square meter. The annual precipitation is 1500-2500mm. The weather in Hainan province is very fit for the cultivation of spirulina and chlorella.