The Winter Goddess by Megan Barnard

A goddess is cursed to endlessly live and die as a mortal until she understands the value of human life, in this inventive, moving reimagining of Irish mythology.

Cailleach, goddess of winter, was not born to be a blight on humanity, but she became one. She would say with scorn that it was their own fault: mortals were selfish, thoughtless, and destructive, bringing harm to each other and the earth without cause or qualms.
One day, Cailleach goes too far. Thousands die, lost to her brutal winter. In punishment, her mother Danu, queen of the gods, strips the goddess of her powers and sends Cailleach to earth, to live and die as the mortals she so despises, until she understands what it is to be one of them. Though determined to live in solitude, Cailleach finds that she cannot help but reach for the people she once held in such disdain. She loves and mourns in equal measure, and in opening herself to humanity, hears tales not meant for immortal ears—including a long-buried secret that will redefine what it means to be a god.