Superstition has it that unless it rains on either the day of Hatsu-uma or the night of the rape blossom festival, which falls on the first day of the serpent in April, a fire will break out.
4月初めの巳の日の菜の花祭りの夜と初午のいずれかに雨が降らないと火に祟られるという俗信がある。