Teru Teru Bouzu is a small Japanese doll made of white paper or cloth, which hangs in windows during the days of rain. According to tradition, an amulet that is to prevent rainy days and attract good weather.
"Teru Teru Bouzu" became popular in the Edo period. Children built these amulets to have a good time the next day, saying the words 'healer of good weather, please let the weather be good tomorrow'. Nowadays children build these amulets with paper tissue or white cloth and hang them in the window with the desire to have a sunny day the next day, often in the days before go to the school trip or a picnic. Hung upside down it means desire to attract rain.
Example from www.deviantart.com-