Kinmen is situated opposite of Xiamen and Tongan along the same latitude line in the subtropical oceanic climate zone. However, Xiamen and Tongan have relatively mild climates and gentle winds blowing because they are next to mountains. Kinmen, on the other hand, has strong winds as it and its islets sit in the sea with lots of hills but no natural protection afforded by mountains. The rainy season is from April through August, and typhoon season is mainly in July and August. The prevailing winds in Kinmen are northeast monsoonal, and blow hard from July to December. The annual average temperature is 20.9°C. The highest monthly average temperature is 28.2°C, in August. The lowest monthly average temperature is 12.8°C, in January. The annual average rainfall is below 1000 mm of which 80% occurs during the period from April to September.
Kinmen's islands are largely composed of granite gneiss, and the soils are mostly sand and bare laterite. The former is a thick layer with poor retention capacity for nutrients and water; the latter is a thin layer of acidic soil with little humus in it. Both are not suitable for farming. Therefore, farmers can only grow low-value drought-resistant crops such as sorghum, corn, peanuts and sweet potatoes. It is difficult to produce a good harvest here.