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The analysis of long-term changes of the major climate variables was conducted using a time series of observations from meteorological stations that had continuous observations from 65 up to 120 years. The surface air temperature in the region is characterized by considerable temporal variability which is most apparent in the winter months and thus in the annual values. The positive regional trends of the surface air temperature vary from 0.2 to 0.6 • C per decade. On a century time scale, a tendency for a reduction of the annual precipitation totals prevails. However, the trend values are much lower than the interannual variability of precipitation.Analyzing the historical climatic conditions of the Baikal Region, we found that the occurrence of drought is possible in any month of the vegetation period, particularly in May, when the maximum numbers of dry years (33-64%), and the years with strong droughts (8-15%) were documented. The influence of climatic conditions on annual wood growth was studied using the response function technique. Results of this analysis show that in the Middle Priangarye region, the greatest impact upon the tree ring growth of pine reflects the mean April temperature, and in the Upper Priangarye region, annual atmospheric precipitation totals (for the hydrological year) control this growth.

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Over the period 1981–2015 severe climatic conditions on the North of Siberia (area within 66–162° E above the Polar Circle) were characterized by significant space-time variations of air temperature at the cold period of the year. This conclusion is made on the basis of analysis of observations made about 13 hour of local time. Positive changes in the mean seasonal air temperature were observed here in October–April. The largest rates of air temperature rise with a pronounced gradient to the West were noted in high latitudes, i.e. in Arctic glacial and polar desert landscapes. The change in weather severity which is one of characteristics of the climate discomfort was analyzed by means of the Arnoldi index (TA). This index reflects the combined effect of negative temperatures and stiff wind on the thermal state of the open surface of the human body. Together with the space-time dynamics of the actual TA values, important values of TA are its threshold values (more than 30 and more than 45 units) which determine a degree of discomfort. Duration of these periods, limiting a possibility of a person's stay in the open air, is also extremely important as well. In recent decades (1981–2015), the spatial differentiation of the number of days (from 80 to 160) limiting the human’s stay in the open air reflects in the main fluctuations of the air temperature and wind regime in polar landscapes. Slight warming (a rise of the air temperature) and small wind speed variability during the period from October to April in 1981–2015 resulted in a certain decrease in the index of weather severity in relation to the period 1966–1980, since the last one did not did not go beyond limit of the interannual variability. Despite the stable increase in the air temperature in 1981–2015, no tendency to reduction of the number of days limiting human’s stay in the open air was noted. The duration of this period for 1981–2015 is similar to that observed in 1936–1964, and we believe that this is suggestive of manifestation of the cyclicity of atmospheric processes and is agreed with a gradual decrease in the rate of the temperature rise. In the last period duration of the period limiting human stay in the open air in the considered area remains high and ranges from 3.5 (to the west of 80° E) to 5 months on islands and capes of the region. So, as is demonstrated by the above example of space-time dynamics of the weather severity index at the time about 13 hours of local time, no decrease in the level of discomfort in polar Siberia is found.

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