The phenomena of drought is common in the world, particularly in Pakistan. Drought in Pakistan has been studied in terms of its spatial and temporal variability, as well as its impact on the El Niño-Southern Oscillation (ENSO) cycle. The objectives of this study are to identify homogeneous rainfall regions and their trend regions, as well as the impact of ENSO cycle. For the analysis, 44 meteorological sites during 1980–2019 are used for monthly rainfall data. The descriptive and exploratory statistics tests (e.g., Pettitt and Mann-Kendall—MK), Sen method, and cluster analysis (CA) are implemented with the annual Standardized Precipitation Index (SPI). The ENSO occurrences were classified based on the Oceanic Nio Index (ONI) for region 3.4. Using the Cophenetic Correlation Coefficient (CCC) and a significance level of 5%, seven approaches were applied to the pluviometric dataset. The CCC > 0.9082 indicates that the Complete approach is the best. According to the CA method, Pakistan has four homogenous rainfall groups (G1, G2, G3, and G4). Descriptive and exploratory statistics yielded lower values for G1 than for the other groups. Pettitt's technique identified the most extreme El Niño years in terms of the drought's spatial and temporal variability. According to the Pettitt test, the wettest months were March, August, September, June, and December. Non-significant increases in Pakistan's annual rainfall were found in the MK test, with exceptions in the southern and northern regions, respectively. No significant rise in Pakistan's rainfall was found using Sen's Sen's approach, especially in the G2, G3, and G4 regions. The severity of the drought in Pakistan is made worse by months, homogeneous groups of rainfall, and El Niño events, all of which require public officials' attention while managing water resources, agriculture, and the country's economy.