A temperature calibrator for calibrating temperature function devices has an outer and an inner housing as well as a calibrator block. The calibrator block is radially spaced from the inner housing to form a flow space. The flow space is in communication with the environment at the upper end and at the lower end to generate a flow. A fan having a fan wheel that can be driven by a motor is connected to the flow space. The fan wheel is formed from a heat-resistant material; and the fan forms a predominantly closed surface in a plan view.