The Rain as a Metaphor
We can say “the rain is gone or “the rain has gone”.
We use the metaphor of a bright clear day with the sun shining to describe our feeling. How does the song make you feel Does it make you happy?
Tell us how you feel in the comments section.
Future “going to”
We say “gonna” instead of “going to” but we do not usually write it in academic or formal language. It is common in speech and in songs.
You can find more examples of this tense at this link:
Future Going to tense