The south wind doesn't know that the north wind is cold, which is a poem written by Du Fu, an ancient Chinese poet.
The whole poem is as follows: leaves fall like the spray of a waterfall, and I watch the long river roll forward. Li in the sad autumn scenery, a wanderer all the year round, lives alone on the high platform in today's illness. After all the hardships and hatred, the white hair is full, and the wine glasses are damaged. The south wind doesn't know that the north wind is cold, and a crane will fly in the sky forever.
The south wind does not know that the north wind is cold. This sentence has far-reaching significance. The south wind is warm and the north wind is cold. People can only feel the temperature of their own environment, and it is difficult to understand the warmth and coldness that others feel. This is a metaphor.
The next sentence "A crane flies in the sky forever" depicts a picture of a crane flying high in the sky, which further deepens the poet's sense of loneliness and detachment from life.