The Song of Storms is an interesting paradox added to the game. The song is taught to adult Link by the man in the Windmill of Kakariko Village. The man says that he learned it from a young child who played the song on his ocarina.
This means that young Link taught the man the song when he plays it 7 years earlier which you have not done, but will need to do later on…. so where exactly did the song come from?
The Song of Storms can be used to open up small holes in the ground in certain areas of the game and is used in the Windmill to drain the water from the bottom of the well.