Hydrologists in developing countries face a major challenge due to the lack of ground data. This study evaluates the performance of the monthly Tropical Rainfall Measurement Mission (TRMM) algorithm 3B43 V7 using 172 ground rainfall measurement stations (GRMS) over Morocco (1998–2018). The performance of the TRMM 3B43 V7 was assessed using four well-known metrics (KGE, R2, PBIAS, and RSR). The evaluation was undertaken based on (1) a point-to-pixel scale, (2) sub-regions of Morocco, (3) climatic zones, and (4) different ranges of altitudes. Results indicate that the TRMM 3B43 V7 provides satisfactory attribution in most regions of Morocco, with an average R2 higher than 0.54, except in the south areas, which have the lowest R2 between 0.29 and 0.41. The best R2 of 0.95 was observed in the Tangier-Tetouan-Al Hoceima region. The other performance criteria (KGE: 0.93, RSR: 0.21, PBIAS: − 5.5) indicate that TRMM 3B43 V7 is consistent with in situ data but slightly underestimated. At the point-to-pixel scale, KGE and R2 show that 61% and 52% of stations present satisfactory to good results, respectively. The PBIAS shows a large overestimation over most parts of Morocco, particularly the southern part. TRMM 3B43V7 performs better in the Mediterranean climate than in other climatic zones. TRMM 3B43 V7 harmonises GRMS slightly in low elevation zones, while average PBIAS show a global overestimation, increasing in high and low elevations. The results of this study confirm that TRMM 3B43 V7 provides a vital baseline tool to assist Moroccan Hydraulic Basin agencies.

Hydrologists in developing countries face a major challenge due to the lack of ground data. This study evaluates the performance of the monthly Tropical Rainfall Measurement Mission (TRMM) algorithm 3B43 V7 using 172 ground rainfall measurement stations (GRMS) over Morocco (1998–2018). The performance of the TRMM 3B43 V7 was assessed using four well-known metrics (KGE, R2, PBIAS, and RSR). The evaluation was undertaken based on (1) a point-to-pixel scale, (2) sub-regions of Morocco, (3) climatic zones, and (4) different ranges of altitudes. Results indicate that the TRMM 3B43 V7 provides satisfactory attribution in most regions of Morocco, with an average R2 higher than 0.54, except in the south areas, which have the lowest R2 between 0.29 and 0.41. The best R2 of 0.95 was observed in the Tangier-Tetouan-Al Hoceima region. The other performance criteria (KGE: 0.93, RSR: 0.21, PBIAS: − 5.5) indicate that TRMM 3B43 V7 is consistent with in situ data but slightly underestimated. At the point-to-pixel scale, KGE and R2 show that 61% and 52% of stations present satisfactory to good results, respectively. The PBIAS shows a large overestimation over most parts of Morocco, particularly the southern part. TRMM 3B43V7 performs better in the Mediterranean climate than in other climatic zones. TRMM 3B43 V7 harmonises GRMS slightly in low elevation zones, while average PBIAS show a global overestimation, increasing in high and low elevations. The results of this study confirm that TRMM 3B43 V7 provides a vital baseline tool to assist Moroccan Hydraulic Basin agencies.