English: The analysis of the daily meteorological data over the past 120 years has shown that in recent decades, the climate of Kyiv became significantly warmer. This is seen from comparing the density function of some temperature indicators by separate 30-year periods for both the year scale and the separate season's scale. As can be seen from the diagram, the density function curve of the average annual temperatures for 1991–2020 is noticeably shifted to the right towards larger temperature values. Compared to previous 30-year periods, the years with an average annual temperature above 8.5 °C in 1991–2020 were observed more often. A similar shifting towards higher temperatures is also observed in the curves of the distribution of average seasons temperatures in the last three decades. So, during 1991-2020, the winters with an average temperature below -3.5 °С in Kyiv were observed more rarely than in any of the previous 30-year periods. As for the spring season, until 1990, the average seasonal temperature below 6 °C was not a rare phenomenon, but after 1990, the average seasonal temperature below 6 °C did not observe at all. Instead, the frequency of spring seasons with the average season temperature above 8.5 °C has substantially increased. As for the summer, the seasons with the average seasonal temperature above 20 °C during the last 30 years were observed more often. The shift of the density function curve for the autumn average season temperature for 1990-2020, compared with other seasons, turned out to be smaller, although it is still quite noticeable. Thus, in the last three decades, the warm autumn seasons with the average seasonal temperature above 9 °C occurred more often than before.

The diagrams are based on the own analysis of the daily meteorological data for Kyiv city. Data processing was carried out in the R software (v. 4.1.2); Diagrams was built using ggplot2 package (v. 3.3.5). The source of the daily temperature dataset: European climate assessment & dataset (ECA&D) (Klein Tank A.M.G. et al. 2002).

Klein Tank A.M.G. et al. 2002. Daily dataset of 20th-century surface air temperature and precipitation series for the European Climate Assessment. Int. J. of Climatol., 22, 1441-1453. Data and metadata available at http://www.ecad.eu