When did the record that snowflakes in China are hexagonal first appear?

According to the cultural relics excavated by archaeologists, China people knew that snowflakes were hexagonal as early as 2 100 years ago. There is a record in the Biography of Han Poetry in BC 135 that "where there are five more flowers, snowflakes are the only six". This shows that the scientific common sense that snowflakes were hexagonal at that time has been widely recognized by Chinese people. It can be seen that the working people in ancient China have already made correct conclusions about many natural phenomena.