Why do meteors appear in the clear night sky?

Meteors are always there. It's just easier to see on a clear night.

When small celestial bodies pass by, meteors are attracted to the earth by the earth's gravitational field. When they enter the earth's atmosphere, they rub with air to generate heat and burn. It usually melts and disappears before landing. It fell to the ground before burning, that is, meteorites, iron ice, Xixi ~ ~