Rainfall data is crucial in civil engineering planning, particularly within the water resources field. A common challenge faced is the limited availability of reliable rainfall data, either due to unavailability or incompleteness. Recently, water resources planning practitioners have increasingly turned to Tropical Rainfall Measuring Mission (TRMM) as a prevalent forecasting method. Therefore, this research aimed to evaluate the precision and reliability of TRMM satellite daily imagery and design rainfall data in comparison with records obtained from ground station rain gauge. To assess TRMM rainfall accuracy, various indicators were employed, including Nash–Sutcliffe Efficiency (NSE), correlation coefficient (R), Root Mean Squared Error (RMSE), and Relative Error (RE). The results showed disparities between TRMM data and the rain gauge recordings at four locations. The NSE values for the five rain gauge stations ranged from − 0.67 to 0.39, with R varying from 0.145 to 0.657. The RMSE yielded values less than 100, while the RE ranged from 0.91 to 1.59. For the analysis of annual maximum daily rainfall, the NSE values ranged between − 0.591 and 0.999, with R ranging from − 0.542 to 0.541. The RMSE remained less than 100, while the RE ranged from 0.26 to 0.36. In the design rainfall analysis, the NSE values ranged from 0.38 to 0.99, with R at 0.999. The RMSE was less than 100, while the RE ranged from 0.07 to 0.36.