In the paper, results of year-long measurements of radon levels in dwellings on the premises of Silesian Voivodeship are presented. Track etched detectors with polymer CR-39 foils were used in the investigations. As the studied buildings were located in different regions of Silesian Voivodeship, therefore results of measurements were analysed due to possible influence of geological structure or effect of mining operations in places, where given dwellings were situated. Elevated concentrations of radon were measured mostly in dwellings located in areas, where permeable Triassic limestone and dolomite occur, as it has been predicted. On the other hand, the impact of mining activity such as disintegration of rock-body and activation of faults plays an important role, too, because it enables radon migration and its entry into buildings. Beside the analysis of seasonal variations of radon activity concentration, the impact of temperature and pressure on these fluctuations outdoor and indoor buildings has been analysed.