<p>This study evaluates the influence of different climate databases on asphalt overlay rutting prediction using FlexPAVE™ software in two locations in the state of Rio Grande do Sul, Brazil. Three climate data sources and two models for calculating temperature profiles were evaluated. The results demonstrate the importance of climate databases in predicting asphalt overlay rutting. For the conditions evaluated, differences of up to 146% in predicted rutting values were observed, primarily influenced by discrepancies in air temperature and wind speed data, which can lead to significant differences in the projected service life of the structures. These differences in simulated values can lead to unrealistic predictions, resulting in the construction of oversized or undersized pavement structures. It was also observed that mixtures with modified binders are less susceptible to pavement temperature variations caused by differences in climate databases. Given the results obtained, it is recommended to adjust air temperature for altitude, critically evaluate wind speed from reanalyses, and adopt a standardized reference climate database for mechanistic-empirical methods calibration. In addition, due to the differences identified in this study, it is considered relevant to expand the analyses of climate databases in Brazil to better understand their impact on predicting pavement distress. Finally, it is important to emphasize that rutting is a multifactorial phenomenon that extends beyond the thermal effects represented in viscoelastic models, involving factors such as axle loads and structural materials. These aspects, not examined in this study, should be incorporated into future research to improve rutting prediction under climatic conditions.</p>