Whistling after dark is widely believed to attract supernatural entities such as ghosts, demons, or spirits. This superstition applies particularly to whistling alone at night, indoors, or in natural settings like forests or mountains. The belief often warns that the act of whistling mimics a call—one that can be mistaken by otherworldly beings as an invitation or challenge.

In cultures where oral traditions have preserved this superstition, the consequences of night whistling range from attracting mischievous spirits to inviting serious danger. The human-like tone of whistling, especially in an otherwise silent or dark environment, has likely contributed to its association with unexplainable phenomena and invisible entities.