The results of testing several RANS turbulence models in solving a problem of free air convection temporal development near the surface of a suddenly heated infinite vertical plate have been presented in the paper. The solution results with the use of the different models were compared with the literature data obtained by direct numerical simulation. Numerical solutions were carried out using the four models, two of them based on the isotropic turbulent viscosity concept and the rest ones involved solving the transport equations of the Reynolds stress tensor components. The flow and heat transfer characteristics for different stages of boundary layer development, from laminar to turbulent, were analyzed. Based on a comparison with the literature data on direct numerical simulation, conclusions about the predictive capabilities of the RANS models considered were drawn.