Chunni and Zhi Zhi know what season Laokang has.

According to Douban.com, Chunni and Zhi Zhi learned the true identity of Lao Kang in the 26th episode of the TV series Chunni's Family War. In fact, the season is not explicitly mentioned, but the audience can infer from the plot background and clues that this secret disclosure took place in winter. It describes the cold climate, people wearing heavy clothes and other elements related to winter.