It's a hot summer night. It rained a little, but I thought it wasn't enough, so I said...
"天 needs to 雨 some more. Maybe it will 涼 my 屋."
Pop quiz: Which tone is 雨?
The answer is
C. 去. The verb 雨 "to rain" is pronounced 王遇切 (yù), i.e. with 去聲. One can check any large dictionary such as 國語辭典.