The data set consists of magnesium (Mg), oxygen (O), and hydrogen (H) isotope signatures and Mg concentrations of monthly collected precipitation and daily snow samples. Samples were collected between December 2014 and June 2017 in the village of Gevelsberg (NW Germany, 51.32°N, 7.32°E) at 206 m above sea level. Rainwater was collected daily using a funnel connected to a 5 liter PET canister. The collected water was transferred into a second canister to store the monthly sample. Snow samples were separately collected on the days of snowfall in ca. 5 m distance to the rainwater collection site using 500 ml PET bottles. The full snow thickness was sampled using a small scoop. All collected monthly and daily snow samples were filtered using 0.45µm cellulose-acetate filters (Sartorius) and stored in a fridge. Subsequent analysis of rain and snow samples include Mg concentration analysis using an ICP-OES (iCAP 6500 DUO, Thermo Fisher Scientific) and Magnesium isotope composition analysis using an MC-ICP-MS Neptune (Thermo Fisher Scientific) at the Ruhr-University Bochum, Germany. Oxygen and hydrogen isotope composition was determined using cavity ring-down spectrometry (L2140i, Picarro) at Innsbruck University, Austria.