The article dwells on climatic and chemical risk factors that influence health of people living in the RF arctic and sub-arctic regions on population and sub-population levels. We used a model describing cause-effect relations between environmental factors and life expectancy at birth based on an artificial neural network to predict a future medical and demographic situation in territories with arctic and sub-arctic climate in the RF. Children’s health was examined profoundly due to a participating representative sampling. We comparatively analyzed clinical, biochemical and general clinical indicators in the test and reference groups using standard statistical procedures and statistical software packages. We established that average monthly temperatures in July grew on average by 3.4 % over 2010–2019 on the examined territories in the RF; precipitations in January and July grew by 13.0–15.1 %. The article presents differentiated estimates of emerging influence on life expectancy at birth (LEB) exerted by weather and climatic conditions on the analyzed territories with arctic and sub-arctic climate. Losses in LEB vary from 164 days in Yakutia to 349 days in Chukotka. Aggregated influence of weather and climatic factors in the arctic and sub-arctic zones in 2010–2019 produced variable effects on LEB, starting from negative ones that resulted in its decline in the Magadan region, the Nenets Autonomous Area, Chukotka, and the Yamal-Nenets Autonomous Area (-254; -211; -109 and -8 days accordingly) and to positive ones that led to the growth in LEB by up to 111 days in Yakutia. Children who are simultaneously exposed to adverse weather and climatic factors in the sub-arctic zone and substantial chemical pollution in ambient air have more frequent and more apparent negative changes in their health indicators in comparison with children from the reference group. Thus, respiratory diseases and diseases of the nervous system were by 5.6 times more frequent in the test group; levels of leukocytes, ESR, TSH, Apo-B and Apo-B/ApoA1 in blood were by 1.3–1.7 times higher, р = 0.0001. Levels of Apo A1, hydrocortisone, and serotonin in blood were by 1.2–2.5 times lower, р = 0.0001–0.040, etc. A share contribution made by chemical factors to associated respiratory diseases and diseases of the nervous system amounted to 25–31 %; adverse climatic factors, 10–15 % .