Yonl or Yuna Yuna
Or Sunny is also good. If you call it rain, come the sun?
Yuki is also very good! Or Yuli Yuli or Yuri Yuri are both good
Yolin! Yes, yes, yes! Youlin, the pronunciation of You is very similar to rain^_^! ?
It’s not bad to call her Yoona! Girls' Generation's Yoona's English name is this, but Yoona is not pronounced as Yoona, but similar to Yua.
Yeol is the Roman pronunciation of Yo, and rain is Yeo. Adding an L makes it look better.