* The Sun is not in the sky. During the day, the Sun's light is so bright that it overwhelms the light from stars, making them invisible. At night, the Sun is on the other side of the Earth, and its light doesn't interfere with our view of the stars.

* The Earth's atmosphere is relatively transparent. While the atmosphere does scatter some light, it allows enough starlight to reach our eyes. This is especially true when the air is clear and there is no cloud cover.

Let me know if you'd like to know more about stars!