Amefurashi: The Rain Goddess

Amefurashi: The Rain Goddess manga summary: Gimmy is just an ordinary teen living in a desert town when his younger twin brother and sister disappear. While searching for them, Gimmy comes face-to-face with a sassy deity, Sora, the rain goddess who provides water to the town. But another goddess, Ciel, wants Sora's sacred tree–so that she can control the rain!