In the traditional culture of China, the phrase "look up at the sky after heavy snow" is often used to describe that as long as you remain optimistic in the face of difficulties, you can see hope and a bright future. This sentence comes from Su Shi's Gan Ming Temple after Snow.
In Su Shi's poems, it is described that after the heavy snow, although the ground was covered with thick snow, Su Shi chose to look up at the sky and saw a picturesque scene of Chu and Qing after the snow. This shows that he is optimistic in difficulties and can see the beauty of life even in the face of difficulties.