Spatial and temporal variation in the isotopic composition of Ethiopian precipitation

•Our precipitation isotope data shows the need for high-frequency spatial sampling.•Daily δ18Oprecip values decrease by >8‰ synchronously at 3 stations in August 2013.•The northwestern highland stations show similar seasonal trends in δ18Oprecip.•Seasonality of δ18Oprecip at Jijiga is less distinct than in northwest highlands.•Storm intensity and convection likely explain seasonal isotope variations.