Why do fortune tellers calculate according to the lunar calendar instead of the solar calendar?

Generally, China's fortune-telling is based on people's gossip. In fact, from the root, fortune-telling has a great relationship with the Book of Changes, which is a book to guide how to improve life energy, teach people to be human and adapt to life. It involves practice, philosophy and divination. Therefore, it has become a classic of Taoism, Confucianism and Yinshu, and these three religions have different understandings and applications in their respective fields. It is the experience of the ancients to sum up the laws of the sun and the moon. Our lunar calendar is based on the laws of the moon's movement. Therefore, ancient divination was based on the lunar calendar. These are my humble opinions.