MA-RAIN v1.0: Consistent Monthly Rainfall Dataset for Maranhão State, Brazil (1987–2023)

MA-RAIN v1.0 is a consistent, quality-controlled, and gap-filled monthly precipitation dataset for Maranhão State, Brazil, covering the period January 1987 to December 2023. The dataset was developed to address the common challenges of incomplete and inconsistent long-term rainfall records in tropical regions, including missing values, irregular sampling, and station discontinuities. Precipitation records were subjected to rigorous quality control, homogenization, and statistical gap-filling to ensure temporal coherence and reliability across the entire period. This approach facilitates accurate climatological analysis, trend detection, and intercomparison with other climatic datasets. MA-RAIN v1.0 provides standardised monthly rainfall totals (in millimetres) at the state scale, supporting research on climate variability, drought, and water-resource assessment, hydrological and ecological modelling, and environmental change studies. The dataset is openly available to enable reproducible science and broad reuse across meteorology, hydrology, climate impact research, and environmental decision-making.