The COBECORE project aims to establish baseline climatological measurements by valorizing climatological legacy data, crucial for reanalysis. This lack of long-term (historical) climatological data leaves the central Congo Basin spatially and temporally under-represented. Even today, the central Congo Basin is currently represented by only a few rain gauges, limiting climate both retrospective analysis and forecasts across the Congo Basin. Here we present the historical context in which measurements were made by La régie des plantations de la colonie (REPCO) and the Institut National d Etudes Agronomique du Congo Belge (INEAC), covering six decades (1901 1960). We discuss the rationale behind the establishment of various measurement stations, the protocols used as well as instrumentation. Our analysis provides contextual information critical to the proper valorization and interpretation of data collected within the COBECORE project.