本文按照我国季风热带气候的特点,根据华南100多个台站近三十年气候资料拟订我国的热带北界,采用了如下气候指标:（1）最冷月均温15℃;（2）极端低温多年平均3℃;（3）绝对低温O℃;（4）年平均霜日1—2天;（5）≥1O℃积温＞500℃;（6）热带天气型日数占各型天气日数约达80%。据此划定的热带北界自粤西高州,东出粤西沿海—珠江口—粤东沿海—台湾中南部沿岸,西延桂南沿岸—滇南西双版纳南部—向南流的各河谷南端及盆地。我国热带成带状,但不很连续,有些成“飞地”插入南亚热带。北界全长约3000km,热带陆地面积约8X10⁴km²。

In this paper, some viewpoints on the tropical climate in China have been given. So far as the boundary of climate is concerned, the low temperature level in winter is to be considered first. The northern boundary of tropical climate in China is determined according to the climatic indices, and referring to the local mountainous topography and the growth of tropical crops. The indices include: (1) The mean temperature of the coldest month 15℃; (2) the annual mean minimun temperature 3℃; (3) the absolute minimum temperature 0℃; (4) almost free of frost or the frost days not more than 2 days; (5) the annual accumulated temperature of the 10℃ period about 7500-8000℃, which is roughly equivalent to annual mean temperature of 22℃; (6) the percentage of the tropical weather type and transitional weather type about 80% of the annual total.On the basis of climatic data of more than 100 stations in South China, the northern boundary of tropical climate is drawn along Gaozhou, Western Guangdong, Southern slope of Yun-kaidashan and Dayunwushan mountains. It is the significant section of the northern boundary of tropical climate in China. There are many local sites suitable for growing rubber trees. Westward, the boundary in Guangxi is drawn on the southern coast and eastward, it is drawn from Yangjiang along the coast, to the mouth of Zhujiang and then along the coast of Eastern Guangdong. In Yunnan province, along Yuanjiang valley, Xishuangbanna, (except Meng-hai County) the boundary reaches westwerd to Menglian, Mengding and Ruili Counties. In southern Taiwan, it passes through the penghu slands first and then across Taizhong, Tainan, Hengchun, and turns northward up to Hualian.Obviously, the northern boundary of tropical climate in China is discontinuous. There are small pockets of tropical climate inserting in o some subtropical areas like separated "island".