Using the daily data on precipitation in Russian and Mongolian Altai from 7 weather stations, as well as the data from «Calendar of sequential change elementary circulation mechanisms (ECM)» (developed by B.L. Dzerdzeevskii), we found the principal microcirculation processes responsible for precipitation in that region during the last thirty years (1981–2011). This period is divided into two time intervals by the sign flip of the climate change tendency which happened around 2000. We showed that the precipitation in Russian Altai in 1981–2000 was mostly due to ECM 13s (south-western cyclones). However, in 2001–2011 the contribution of this type of ECM decreased in average on 8,36%, but at the same time the contribution of ECM 12а (combined influence of the Arctic anticyclone and southwestern cyclones) has increased. In Mongolian Altai the contributions of various ECMs 13s, 12a and 9a differ by about 8% which signifies a redistribution of relative contributions of the ECMs responsible for the precipitation in the North of Mongolian Altai. Our analysis allowed splitting the stations into 4 groups having similar distributions of the ECMs. Since Kosh-Agach (Russian Altai) and Ulgiy (Mongolian Altai) weather stations turn out to belong to the same group, it seems possible to use the Kosh-Agach station, providing the longest data set, to estimate the precipitation in the northern regions of Mongolian Altai.