Despite its importance for tourism and rural development, the biogeographic status of semi-desert and savanna transition inselbergs and mountains in central Namibia is poorly known. This study therefore investigates 11 inselbergs and their mountain flora in the central Namib Desert with regard to biogeographic patterns. Variation between seasons in variable environments is one of the most critical factors biasing global biodiversity analyses, and often results in lack of biogeographic analysis in these areas altogether. This study shows that patterns in floristic measures were largely maintained when a subset of the data was analyzed that contained only perennial plants (which are visible at these sites also during a poor rainy reason). This approach may hence be adapted in other areas that experience similar problems in data coverage related to seasonal differences. Keywords: Biogeography, inselbergs, central Namib, sampling effort, savanna transition, southern Africa.