Hand radiograms for osseographic assessment of bone aging status were taken from more than 7,500 individuals residing in 31 different localities and belonging to 20 ethnic groups. Multiple regression analysis was used to evaluate possible associations between bone aging parameters and several climatic factors, to wit: hours of daylight in January and July, average monthly humidity and partial vapor pressure in January and July, and one climatic index pertaining to comfort conditions in life, namely, the Bioclimatic Index of Severity of Climatic Regime. Multiple regression analysis clearly pointed to significant correlations between climatic characteristics and indices defining the relative rate of bone aging in humans; it also evinced an independent contribution of July's humidity and January's mean temperature to earliest age at which first signs of bone aging can be found. In sum, there are grounds for concluding that temperature and humidity are key factors in triggering initial bone changes in individuals within the human populations prone to environmental effects. The combination of humidity and temperature with other factors which reflect the sharpness of the interseasonal differences in climatic conditions predispose the populations to early onset of bone changes.