What does it mean to go back to Nantian?

Going back to Nantian means that the house is seriously wet, and the walls, floors and even ceilings are dripping. This is a natural phenomenon, which occurs mostly in South China, such as Guangdong, Guangxi and southern Fujian. Due to the large temperature difference between indoor and outdoor, it often occurs in early spring. When the early spring turns from winter to spring, it is suppressed by cold air for a long time. Suddenly, the warm and humid airflow in the south moved northward, bringing abundant water vapor and high temperature, which was stronger than the cold air in the north, and the temperature rose rapidly. But the indoor temperature is relatively slow, which leads to the temperature being lower than the outdoor temperature. When strong water vapor enters the room, it will form condensation effect when it is cold, and the gas will become liquid and form water droplets. This is the reason why huinantian appeared.

It has little effect on the general dehumidification around the south sky, such as laying newspapers and sprinkling lime, which requires professional dehumidification. Dehumidifier can dehumidify, adjust humidity by reducing air humidity, control humidity range, and reduce indoor moisture regain and moisture regain.