How can I make background audio change with the time of day?

Hello, I am working on designing an environment for my class, and I wanted to know if it was possible to make a script or function where I can have a background clip play for day time and a different one play at the night. I do already have a day/night cycle.

I attached the day and night cycle script below.

 

Sure, why not? You could have two AudioSource references, and call .Play on the appropriate one. Or, you could have a single AudioSource and two AudioClip references, and then assign the appropriate clip to the AudioSource before telling it to play.

I guess I'm not clear on exactly what the difficulty is you're having.