1. This study introduces a novel approach for quantitatively assessing sea-surface paleotemperatures exemplified in the study of the Upper Paleozoic of Siberia. 2. The method relies on the evaluation of the taxonomic composition of biota. It utilizes a comprehensive dataset encompassing the geographic distribution and ecology of various biotic groups in Siberia and adjacent regions, leveraging the newly developed PaleoSib database. Fossils collected from individual locations often exhibit a wide spectrum of paleotemperatures. 3. To address this variability, we developed an algorithm for calculating average biotic paleotemperatures in each locality/time slice. Utilizing the PaleoSib database, our computations have unveiled a coherent pattern of paleoclimate dynamics, particularly Sea Surface Temperature, across Siberian basins during the Late Paleozoic era. 4. These findings significantly contribute to a refined comprehension of paleoclimate and paleotectonic dynamics in the region during that specific time. To enhance paleotemperature analyses, we have integrated lithological indices with biotic ones, fortifying the overall methodology and furnishing a more robust framework for interpreting paleoclimate data. We aim to incorporate this method into the Paleobiology Database, enhancing its accessibility and fostering its adoption by the broader scientific community.