In this study, we investigated the climatic factors controlling the spatial distribution and annual variation of Î´13C and Î´18O values in Korean rice on a national scale. A total of 480 Korean rice samples were collected in 2016, 2017, and 2018. The spatial distribution of Î´13C and Î´18O values of Korean rice was unclear, with significant inter-annual variability observed at the national scale. Isotopic variability was closely related to climatic conditions, especially precipitation. Overall, rice Î´13C values were negatively correlated with precipitation and sunshine hour. Rice Î´18O values were also strongly negatively correlated with precipitation. Increased precipitation during the growing season (August to October) was mainly linked to lower Î´13C and Î´18O values due to plant physiological processes and/or the contribution of water from different sources to irrigation. All rights reserved, Elsevier.