A global sensitivity analysis is carried out to assess the impact of several parameters on the urban climate of a district in Strasbourg city. The Sobol method is used to analyze simulations of the microclimate model Urban Weather Generator (UWG). The study involves 13 parameters for which different ranges of values are investigated. These parameters characterize urban configuration, materials, vegetation and anthropogenic heat emissions. The results indicate that urban building density, grass and tree cover are the most influential factors on local urban temperatures. Building density contributes to 54.8% of the temperature variance, while vegetation and trees significantly reduce temperatures (20.3% and 15.7% of variance, respectively). These findings highlight the importance of urban planning that incorporates vegetation to mitigate urban heat islands and enhance climate resilience.