What figurative language is the hot sun peeked out of the clouds

This is personification.

The figurate language used in this sentence is personification.

Explanation:

Personification refers to giving objects or animals human characteristics and properties, making them speak, act and think as a human being. In this case, the sun is doing an action attributed to humans. In real life, the sun does not have reasonable thinking, hence he cannot decide to be visible.