Quantitative assessment of the territory continentality is an urgent task, because in the conditions of climate change, the index of continentality can be taken into account when developing geographical forecasts of landscape development. The purpose of this study is to assess the change in the index of continentality of Western Siberia in the conditions of the current trend in climate development. The statistical series of observations on seven meteorological stations in Western Siberia served as the information base of the study. The long-term changes in the average January and average July temperatures, as well as the amount of precipitation for the cold (October-March) and warm (April-September) periods of the year were analyzed. Calculations for the time intervals of 1961–1990 and 1991–2015 allowed us to conclude that the climate continentality of Western Siberia is weakening under the conditions of regional climate development.