Abstract <p>The problem of changing regional climatic conditions, and especially the aridization of the natural environment of arid regions of Russia in connection with global warming, is extremely relevant at the present time. It has led to the study and publication of a significant number of research results on changes in the main meteorological elements—temperature and precipitation on the territory of the Republic of Kalmykia, where the lack of moisture supply and the deficit of its own water resources limit economic development and are unfavorable for the population to live in. The research conducted and publications are aimed at identifying the spatial and temporal variability of meteorological conditions and humidity in the territory of Kalmykia in different time periods, from one year to half a century. However, there are still no studies characterizing climate norms in the basic climate periods established by the World Meteorological Organization. The results presented in this article are original and for the first time characterize two adjacent basic climatic periods 1961–1990 and 1991–2020 and the differences between them in terms of their main parameters. The temperature and precipitation norms for these periods in Kalmykia were determined by calculation based on daily data obtained from the archive of the All-Russia Research Institute of Hydrometeorological Information for two meteorological stations included in the system of the World Meteorological Organization, Elista and Yashkul. For the first period (19961–1990), the normal average annual temperature values at meteorological stations are 9.3 and 10.2°C; for the second period, 10.2 and 11.2°C. The normal annual precipitation for the first period is 344.1 and 244.1 mm, and for the second, 385.3 and 281.6 mm. A comparison of the two periods according to climate norms revealed that the second period at both weather stations was warmer by almost 1°C (0.9 and 1.0°C), and the precipitation norm was almost 40 mm higher (41.1 and 37.5 mm). The study of the direction of temperature and precipitation changes within climatic periods made it possible to identify the presence of a statistically significant positive trend in the change in average annual temperature in the second period at both meteorological stations and a negative statistically significant trend in the change in annual precipitation according to the Yashkul meteorological station. The change in temperature occurred mainly due to an increase in the values of the winter and summer seasons, and precipitation change is mainly due to an increase in precipitation in the autumn and partly spring season, as well as a noticeable decrease in the summer season. Comparison of the obtained characteristics of changes in the temperature and precipitation norms of two climatic periods in Kalmykia with similar results of the World Meteorological Organization for Russia shows that the reduction in summer precipitation in Kalmykia is consistent with the general trend in the country, but temperatures in Kalmykia are rising no more slowly than in the country as a whole, but faster than in the previous period. The established trends of increasing temperature and decreasing precipitation throughout the entire observation period in both the steppe and desert parts of Kalmykia can be assessed as a deterioration in the moisture supply conditions of the territory.</p>