Topographic depressions in high mountain karst regions are among the coldest known areas not only in a regional context but also on a global scale, which is why they are also referred to as frost hollows. Although knowledge of thermal conditions in depressions is generally well established, scientific research on microclimates and periglacial ecosystems in glacio-karstic depressions of the High Dinaric Mountains is scarce and suffers from a lack of continuous data collection. Due to the prevailing natural chemical weathering processes in the limestone areas, karst landscapes with a large number of karst depressions, e.g., dolines, uvalas, and poljes, are characteristic in this region. They provide specific types of microclimates with adequate ecological conditions for cold-adapted species and are interesting geo- and biodiversity sites. Their occurrence indicates migrations during the cold phases of the Pleistocene glacial cycles, in the reverse direction along the north–south axis to the Balkans. The paper deals with temperature conditions and combined plant species as ecological indicators of biological feedbacks to the exceptional frost hollow microclimates in periglacial areas in the Dinaric Mountains of Montenegro. The study area covers the altitudes between 1,200 and 2,026 m in the mountain karst plateau of Sinjajevina Mountains, the Orjen massif, and the Durmitor Mountains. The related fieldwork analyses and continuous measurements were carried out in representative plots in the study area. Strikingly, the results show that the absolute lowest temperatures for the whole Montenegro are found in Durmitor Mountains.