The bachelor thesis deals with the development of climatological conditions in Zvolen basin focused on air temperature. I consider it is important to deal with this subject, as today the issue of climate change and its impact on forest ecosystems and nature is as such a highly discussed issue not only among experts but also among the general public. The work is focused on evaluation of air temperature characteristics of three localities (Borová hora, Kráľová nad Zvolenom and Poľana), which represent representatives of three different vegetation stages (2nd, 4th and 7th vegetation stage). Average air temperatures over a time period (2008–2018) with long-term averages (1961–1990) are compared. The development of the number of summer days, tropical days, frost days and icy days as well as the length of the large and main vegetation period was also analysed. In the case of the average temperature, almost all years were rated as extremely abnormal at all monitored stations. The trend of the number of summer days and tropical days has been growing, with a more pronounced increasing course at lower altitudes. On the contrary, the number of frost days and ice days had a decreasing course with a significant decreasing course in higher altitude. The development of the vegetation periods had only a modest decreasing trend.