Why does Lingnan in China have the characteristics of "it's summer all the time, and it's autumn when it rains"?

"It is summer all the year round, and it rains in autumn" is mainly determined by geographical latitude and topographic conditions.

Latitude, as can be seen from the map, the Tropic of Cancer is passing through the central parts of Taiwan Province, Guangdong and Guangxi provinces. If divided by geographical latitude, the south of this line is tropical, and the north of this line belongs to subtropical. If divided by the isotherm of1October 65438+10℃, this isotherm passes through the northwest and southwest of Fuzhou, Shaoguan in Guangdong and Liuzhou and Baise in Guangxi, and the south of the line is an area without winter all the year round. Therefore, in terms of geographical latitude, Lingnan in China lies between the tropics and subtropics, and most of them are areas without winter.

In terms of topographical conditions, Nanling Mountain ranges from Wuling Mountain in northern Guangxi to Guangdong Province in the west and Wuyi Mountain in the west of Fujian Province in the east. Its height is generally around 1000 ~ 1500m, which can block the cold air from the north to the south in winter, although sometimes the strong cold wave in the north can reach Lingnan, which can reduce the daily average temperature in Guangzhou and Nanning to 4. Moreover, the terrain here is high in the north and low in the south (high in the west and low in the east of Fujian), which is conducive to receiving warm and humid airflow from the ocean, making the climate here warmer and wetter, so the terrain conditions are also one of the main reasons for the warm and hot climate here.

Due to the above two factors, Lingnan has become the warmest region in China. In fact, the climate here is not divided into four seasons, but into three seasons: cool season, 165438+ 10 ~ February, the northeast monsoon prevails and the climate is the coolest; In the warm season, from March to June, the warm and humid air flow at sea begins to enter, the temperature rises and there is more precipitation; In midsummer season, from June to 10, typhoons often strike, with the hottest weather and the most precipitation. During this period, the daily variation of temperature is also the largest, and the temperature can rise and fall by 6 ~ 8℃ in one day. Therefore, "a rain turns into autumn" is truly in line with objective reality.