The paper presents results of the research on the impact of solar radiation on the formation of the thermal conditions of the exposed rock surfaces of the Kraków-Częstochowa Upland. The research comprised the structure of the radiation balance of the active surface of the bottom of the canyon, the temperature of the surface and the layer at the depth of −5 cm in limestone rock on the southern wall of the canyon. The tests were performed in various types of weather. The strongest mesoclimate contrasts were observed in the radiation type of weather: differences in insolation and in the balance of radiation, thermal differences and variations within the heat flux in the rock. The longwave stream of radiation which was emitted by the heated rocks exerted an impact on the microclimate conditions and on the radiation balance at the bottom of the canyon during the night. A diverse relief of the terrain constituted a local factor differentiating the radiation balance and the distribution of the rock temperature. The quantitatively determined structure of the radiation balance and the thermal contrasts of the canyon, particularly of the rock surfaces, point to the importance of the relief in shaping the mesoclimate of even small karst areas. These characteristics determine the heat flux in the rock, weathering processes and others. The mesoclimate and microclimate of the rocks affect the biodiversity of the rock surfaces of the Kraków-Częstochowa Upland. In addition, they shape the ecotopy of the karst canyon, among others – the vegetation on the limestone rocks.