Wind of 120 days (Persian: باد صد و بیست روزه) is a strong Summer wind that blows from late in May to late in September in the east and southeast of the Iranian Plateau. It's known as wind of 120 days because it blows for four months. The usual speed of the wind is around 30–40 km per hour or less, but seldom it can exceed 100–110 km per hour. The direction of the wind is fairly constant. Wind of 120 days is one of the two well-known winds in Iran, the other being Shamal.
The wind originates from the central deserts in Iran and blows toward Sistan and Baluchestan Province. It's hot and carries abrasive sand and particles. This wind together with a high temperature is a cause of intense evaporation of sheets of water in Sistan.