This article examines various annual trends in climate and hydrological changes in Slovenia's mountain regions between 1961 and 2018. Climate changes are primarily reflected in the increase in average annual temperatures and significantly decreased duration of snow cover, and hydrological changes in the decrease in the minimum and mean annual discharge, whereas the maximum discharge is increasing in some places. Among the factors affecting the reduction in the annual water volume in rivers, land-use changes (i.e, increased forest cover) especially stand out. In addition to the water volume, rivers' discharge regimes are also changing. In nearly all locations, the autumn maximum discharge now exceeds the spring maximum discharge, which was once one of the basic characteristics of mountain snow-rain discharge regimes.