A simple method to derive the temperature profile in a superconducting magnet during a quench from measured voltage signals is described. The method was applied to several Large Hadron Collider single aperture dipole models. These measurements show the strong correlation between parameters of the magnet protection system and powering on the one hand and the resulting temperature gradient in the magnet coil on the other. The method allows the localisation of critical points in the magnet design, in particular, the efficiency of the magnet protection system can be evaluated