Temperature determines chemical and physical processes in water bodies as well as it limits the occurrence of stenothermic organisms. Streams, which cross urban areas undergo very often strong alterations in their original appearance and state. This study assesses the impact of urbanization on the temperature regime and heat budget of a creek. The Lockwitzbach in Dresden (Germany), was equipped with four temperature sensors and two discharge gauges at two stream sections, all data are recorded with five minutes resolution. The upstream section is located outside of the city and shows rural characteristics, the downstream section lies within the city of Dresden and represents an urban stream section. The study analyses one year of recordings and concludes that the urban and natural sections show significantly differing temperature dynamics, especially during the summer. Maximum daily temperatures are up to 8.3° C higher in the urban stream section and the mean daily temperature amplitude is 0,9° C or 21∆ rural = 3,4° C; ∆ urban = 4,3° C). Thermal budget of the stream in the city area shows, a mitigating effect on the urban climate. Especially, during summer months with a mean of 35 MW during storm events (May-Sept. ‘17). In contrast, the sensitive heat flux from the stream provides in average 1.6 MW to its surroundings in winter (Jan.-Feb. ‘18). The ecosystem of urban streams is challenged by hydraulic and thermal impacts. On the other hand, running waters in an urban environment greatly mitigate urban climate.