This paper represents the comparison of the calculated and measured temperature field in the direct-chill semi-continuous casting of 0.285[m] diameter extrusion billets from Al4.5%Cu alloy. The steady-state thermal field problem relies on the one-phase physical model, realistic physical properties and process specific boundary conditions. It is solved by using the recently developed dual reciprocity boundary element method which incorporates Laplace equation fundamental solution weighting and scaled augmented thin plate splines. The temperature field is measured through immersion of the thermocouples attached to a specially designed guide support into the casting system. The results of the computational model give excellent agreement with the measured data.