This paper presents the development of a simulation model, which was incorporated into a GIS in order to calculate the maximum intensity of ur-ban heat islands based on urban geometry data. The methodology of this study is based on a theoretical-numerical basis (Oke’s model), followed by the development of a calculation algorithm incorporated into the GIS plat-form, which is then submitted to an adjustment and used as exemplifica-tion. The results show that for the same value of H/W ratio, urban canyons with greater roughness result in lower heat island intensity values in rela-tion to the less rough canyons.