Numerical simulations and experimental results are presented for a 60 year old buttress dam, subjected to temperature variations. The dam has several cracks, that likely have originated from temperature variations. The first step of the analyses was to recreate the current crack-pattern of the dam, by simulating cyclic seasonal temperature variations. After this, detailed simulations of the temperature variation were performed to compare the numerical results with the variations in crack widths and displacements measured for one year. The finite element model shows good agreement with the observed crack-pattern and the measured variations in crack widths and displacements.