O₃ concentrations were monitored between 2006 and 2012 in rural environments in the Štiavnické and Kremnické mountains (the western Carpathian region). There were no spatial differences between the two sites. On the other hand, distinct temporal variations were noticed especially during 2006-08 and 2009-12, with O₃ levels ranging between 36-77 and 42-84 μg·m^-3 in the Štiavnickés and Kremnickés, respectively. Higher O₃ levels correlated with the increases in ambient temperatures and were recorded simultaneously. The maximum mean annual O₃ levels were recorded in 2008, representing 144 μg·m^-3 and 116 μg·m^-3 in both ranges in 2012. The standard deviations as well as standard errors were low in both localities, with the variability lower in the Kremnickés. The minimum annual O₃ levels were observed in 2010, falling to 20.0 μg·m^-3 at both sites. The seasonal maxima were recorded in summer. The ozone values at both sites were more influenced by temperature than by rainfall. The situation of the ground level ozone formation in the studied localities has not been levelled off so far; its developmental trend is not explicit. The occurrence of extreme ozone events is evident, and the associated environmental is serious.