Cosmic rays are high-energy particles with velocities close to the speed of light that have an effect on atmospheric processes. Clouds play a key role in the energy budget of Earth’s surface and lower atmosphere. So, small changes in amount and distribution of clouds or solar irradiance properties can have significant effects on the climate. Researches have shown that solar variations may be linked to climate change through a chain of solar winds, galactic cosmic rays, and total cloud cover. In this paper, the effect of galactic cosmic rays on low cloud cover on a monthly average at Shiraz station was investigated. The results show that changes in galactic cosmic radiation are consistent with low cloud changes.