Why is the sentence in such cold weather changed to in? Why can't it be used?

Usage of on: 1, physical contact, on what. For example, on the table. On the bus. Apples tied to trees are also used. . Put (figuratively) on sth. We live on rice. We live on rice. I have something on my mind. I have something on my mind. 3. Continue without interruption. On duty. On duty on the way to school. On my way to school. 4. Specify the date and time. Sunday. On my birthday. 5, said the continuous relationship of things. Put it on, put it on, put it on. Read this letter. She cried. He cried as soon as he read the letter. Wait .. ln Usage: 1, in physical space. For example, in class. In your. Hands. 2. In the abstract space. Like being in love. In love. There is a deficit. 3. In space. Like the past. A week later. A week later. The problem belongs to a space in such cold weather, so it is now.