This paper introduces a new climatic wind tunnel laboratory, which is one of the laboratories of the Institute of Theoretical and Applied Mechanics (ITAM ) of the Academy of Science of the Czech Republic. The tunnel is used for fundamental research in civil engineering, architecture, and heritage care and in other fields where wind effects appear along with other factors. The paper includes essential information about the interior layout of the tunnel, descriptions of the principal parts of the tunnel which were designed taking into account both the optimal flow characteristics together with the description of some facilities serving for the simulation of a strong wind, rain, freeze and heat radiation, and the modelling of the atmospheric boundary layer. A design for a rectangular contraction nozzle, based on a parabolic profile and extending the capacity of the wind tunnel is presented.