[en] Data of variations in natural background γ-radiation flux density obtained from observations near the ground surface made for a period of almost 1 year are given together with data on simultaneous measurements on changes in various environmental influencing factors, such as the degree of soil dryness, atmospheric radon daughter concentration and rainfall rate. Statistical and time series analyses of these data have provided much information on the relationships between the flux density and influencing factors and periodical characteristics of those variations in the natural environment. It is concluded from the results of the analyses that the atmospheric randon daughters and rainfall play an important role in short- and middle-term variations in the background radiation flux, while the change of soil dryness contributes to long-term variations. (author)