In the current study, the authors present a brief overview of the main factors that affect the processes of heat and mass transfer in the urban environment, and also consider the possibilities of using the ANSYS Fluent software to simulate urban climate problems. A test configuration, which corresponds to the open experimental data, was chosen for the numerical simulation. The boundary and initial conditions for the configuration were set in such a way as to reproduce the conditions of the weakly-unstable thermal stratification of the air flow. Satisfactory agreement of the experimental and simulation data on velocity and temperature profiles was obtained.