Abstract: The evaluation of the urban ecosystem conditions and environment while cities that are still growing economically, are highly necessary for reliable assessment of sustainability in big cities. The urban green spaces are valuable sources of evapotranspiration process generated by trees and vegetation which mitigates urban heat islands (UHI) in the cities. The Land Surface Temperature (LST) is closely related to the distribution of Land Use and Land Cover (LULC) characteristics and can be used as an indicator of the urban environment conditions and development. This research evaluates the patterns of LST distribution by means the Thermal Spatial Distribution Signature (TSDS) procedure using Thermal Infrared (TIR) data obtained from Landsat-5 Thematic Mapper (TM). A set of eighteen images, between 1985 and 2009, were used to study the urban environment during the summer season, in 47 neighborhoods in the city of Porto Alegre, Brazil. At neighborhood scale, results show a non-linear inverse correlation (R2=0.55) between vegetation index and LST. The overall average of the LST is 300.23 K (27.8˚C) with a standard deviation of 1.25 K. The max difference found between neighborhoods was 2.83 K.