extremely hot and dry local wind in Arabia and the Sahara. Its temperature often reaches 55 °C (about 130 °F), and the humidity of the air sometimes falls below 10 percent. It is caused by intensive ground heating under a cloudless sky. Simoom is an Arabic word that means “poison wind.” It refers to the wind's tendency to cause heatstroke as it brings more heat to the human body than is removed by the evaporation of perspiration.