A method to monitor and control the temperature of a sample holder of a laboratory instrument during execution of a temperature profile on the sample holder is presented. The laboratory instrument comprises a sample holder with high temperature uniformity and at least three identical temperature sensors. The measured actual temperatures of the sample holder are processed in order to determine if the execution of the temperature profile should be continued or aborted. Furthermore, temperature sensors which measure actual temperatures that do not fulfil certain requirements are excluded from further monitoring and controlling the temperature of a sample holder.