ABSTRACT: Ensuring safe and productive operations in open pit mining entails undertaking displacement measurement of rock slopes to determine their stability. At Higashi Shikagoe limestone quarry in Hokkaido, Japan, Automated Polar System (APS) was installed to monitor rock slope displacement. The site is geologically complex and is subject to a wide variety of weather conditions due to its location in a cold region of Japan where winter temperatures can drop to −18ºC and snow depths of about 80 to 90 cm are often measured. In this study, APS data was used to characterize rock slope deformation and identify its driving forces. Analysis of displacement data revealed changes in tendencies of displacement during warm and cold periods. Numerical analysis using linearly elastic and isotropic models of the quarry showed that excavation and backfilling were not the main causes of measured displacement. It was found that snowfall and snowmelt had an influence on rock slope displacement.