Why does it never snow in Dongguan?

Because the direct point of the sun is near the Tropic of Capricorn in winter, China is mainly affected by the westerlies weather system. Once the strong cold air affects the southern part of China, it is very likely to snow south of the Qinling-Huaihe line in China.

First of all, China's winter cooling is a cumulative process. Generally speaking, most areas south of Nanling Mountain are near the Tropic of Cancer, even south of the Tropic of Cancer, and get more short-wave solar radiation. The bottom of the westerly trough may not affect these areas. The northwest wind behind the trough is not enough to make cold air reach the area, so it turns into southwest warm and humid airflow, which makes the cooling situation in this area not obvious.

Secondly, Dongguan is a coastal area. It is well known that the sea temperature is higher than the land temperature in winter. If it weren't for high latitudes, the ocean wouldn't freeze. Due to the regulation of land-sea circulation, the temperature in these areas is not easy to drop very low.

There are still many strong cold air affecting China, which can sometimes reduce the temperature below 0 degrees in the coastal areas of South China. When the historical lowest temperature in the southwest coastal area of Guangdong is -2 degrees, the water vapor in the high altitude can also condense into a solid state and fall. However, with the increase of temperature, the air pressure increases, and the friction between the solid falling body and the atmosphere leads to the high temperature of the falling body, which will also become liquid when it falls on the ground.

These are the reasons why there is less snow south of Nanling.