Two-year daily precipitation stable isotope dataset (δ18O and δ2H) from a continental station in NW Croatia

The stable water isotopic composition (δ¹⁸O and δ²H) of daily precipitation from north-western Croatia (near Samobor town) is presented. The dataset includes a total of 288 precipitation samples collected from December 2022 to November 2024. The collection period roughly covered a 24-hour cycle, starting predominantly early in the morning. Stable hydrogen and oxygen isotope analyses of the samples were carried out using a Picarro L2130-i Isotope analyzer, with a precision of 1 ‰ for δ²H and 0.2 ‰ for δ¹⁸O. The raw isotopic data of the precipitation samples are presented in δ-notation (‰) normalized to the international standard VSMOW (Vienna Standard Mean Ocean Water). Additionally, the d-excess values for each sample and the Local meteoric water line (LMWL) were calculated. Presented data were used to investigate the main drivers of stable isotope variability in Croatia and were published in the research article entitled "Assessing the influence of climatic parameters and moisture sources on precipitation isotope composition from central Croatia: Insights from a two-year long daily-resolved dataset". In addition to studying the isotope effects in modern precipitation, this dataset can also be used in palaeoclimate investigations that utilize natural climate archives, as well as environmental studies, including tracking of water pollutants and water resource management.