Considering the vital importance of precipitation in the environment, knowing how it changes over time and its hidden features can be effective in optimizing management plans and environmental planning. In the current research, an attempt was made to reveal the trend of temporal changes and cycles in Iran's rainfall by using Esfazari data in the period from 1970 to 2016 and evaluate it in the form of a cell analysis. The results of the surveys showed that the trend of precipitation changes in 81.4% of the country's area was decreasing. The factors causing this decrease include changes in the mechanism and path of Siberian high-pressure systems and Mediterranean and Sudanese rainfall systems. Investigations revealed the existence of annual cycles that overlapped with each other in some cases and occurred in periods of 1 to 5, 2 to 6, and 2 to 3 years. The analysis of the causes of existence of these cycles, in addition to local factors and medium-scale systems passing through the country, proved the effect of macro-scale atmospheric systems such as Southern Oscillation (ENSO), Indian Ocean Oscillation (Monsoon) and Biennial Oscillation (QBO).