The dataset provides detailed information about the stable isotope composition of different precipitation types (rainfall, fog, throughfall). It was manually collected on up to 9 study plots generally on a weekly basis between November 2012 and November 2014.The following map shows the distribution of the study plots on the southern slopes of Mt. Kilimanjaro. The study plots span across an altitude gradient rising from 950 m to nearly 4,000 m a.s.l. The plot IDs are the ones used within the respective research group. Moisture sources (- 96 hours) of the isotope samples were estimated using backward trajectory computations with the HYSPLIT model (https://www.ready.noaa.gov/HYSPLIT.php) and the R opentraj package (Thalles Santos Silva (2014). opentraj: Tools for Creating and Analysing Air Trajectory Data. R package version 1.0. https://cran.r-project.org/package=opentraj). Reanalysis data was taken from NCEP/NCAR version 2 ( https://www.ncdc.noaa.gov/data-access/model-data/model-datasets/reanalysis-1-reanalysis-2).