A raining day

Rain Rrain go away, but [1]you come back inat another time with your grey sky,.

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[1] Are you asking or wanting the rain to come back? Or just stating that it will?

A raining day

Rain Rain go away, but you back in other time with your grey sky,

Correction

Rain rain go away, but you can come back at another time with your gray sky. 

Correction #2

Rain rain go away, come back when the sky is gray. 

(Are you asking for the rain to return? Or are you just making a casual forecast of the weather? )