Have you ever found out why the summer sky is so clear and bright that you can see many stars clearly? The winter night is much more blurred?

Because in summer, our night sky faces the center of the Milky Way, and in winter, it faces the outside. The distribution of stars in the Milky Way is uneven. The denser the stars, the brighter the Milky Way in summer and the more blurred it is in winter. In addition, the clouds are thin in summer and much thicker in winter, which will block the line of sight.