In the present paper, the flow and temperature fields in a 20 kg silicon Czochralski melt were studied by 3D, time-dependent numerical simulation using the real melt geometry and realistic thermal boundary conditions for different types of magnetic fields. The numerical results are compared directly with temperature distributions obtained experimentally for the same parameter as in the numerical simulations. It is found that the main characteristics of the experimentally observed temperature distributions are fairly well reproduced by the 3D simulations, although there still exist some quantitative discrepancies.