Supplement 1. Rainfall sample data including the measured stable isotope values, rainfall amounts, collection dates and times, and meteorological data at the collection site.

File List tableS1.csv (MD5: 306d75dd4671708b43a7f0157d0de694) Description This file provides the original data for the rainfall samples (tableS1.csv) that forms the basis of the analysis presented in the main article. This supplemental data is provided here to give additional detail to the analysis. Variable descriptions are in Supplement 2, column 2. Additionally, for the “Season” variable (tableS1.csv, column 2), “D” refers to the Dry Season, “L” to the Long Rains, “C” to the Continental Rains, and “S” to Short Rains (see the main text for the season cutoff dates). The date and time provided for each rain sample (tableS1.csv, columns 3 through 6, in local time for Kenya which is GMT +3) represents the first hour of the rain event and the “Event Duration [hr]” column provides the length of the rain event represented by the each sample. The “NAN” flag appears where no data is available. In Supplement 2, the values represent the Pearson correlation coefficient for the corresponding row and column variables, and an absolute value greater than 0.31 is statistically significant (<i>P</i> &lt; 0.05, two-tailed).