Synopsis (from MAL)

When club activities end early due to rain, Shigure Kurimoto returns to the audiovisual room to retrieve something he forgot—and there, he meets a lone girl named Junna Amamori. Sharing similar tastes in books and music, the two begin to meet secretly on rainy afternoons after school, when their schedules align.

"I like the name Shigure."

"I prefer being alone and don't want to deal with unnecessary people... but if it's you, Shigure, I don't mind."

Junna, who only appears on damp, rainy days, is expressionless and dry in demeanor, yet oddly close in proximity and eager for affection. Then, on a sunny day, Shigure discovers Junna's "secret"—and from that moment, the distance between them shrinks to the point where he can feel her breath. Her overwhelming affection begins to spill out uncontrollably...

3 vols of LN so far, and the manga just started recently I think. Though I don't know the prospect of this getting licensed, given that someone already translated all 3 vols, but I just got addicted recently, so it's good if this gets licensed :D