Sun Up To Sun Down.

Riddle: When the sun is up, you can see right through me. But when the sun is gone, and the lights are on, you see yourself. What am I?

Answer: A window.

Source: https://www.riddles.com/7890

When the sun is up, you can see right through me. But when the sun is gone, and the lights are on, you see yourself. What am I? — Sun up to sun down. by Joejoe v1.

Riddle: When the sun is up, you can see right through me. But when the sun is gone, and the lights are on, you see yourself. What am I? Answer: A window. — by Joejoe v2.