A temperature measurement appliance for contactless temperature measurement, in particular a handheld temperature measurement appliance, includes a housing and at least one sensor that is disposed on the housing. The at least one sensor is configured to measure one or more of a relative air humidity and an ambient temperature. The temperature measurement appliance further includes at least one protective cap that is configured to be reversibly arranged on the temperature measurement appliance so as to mechanically protect the at least one sensor. The temperature measurement appliance further includes one or more features arranged on the temperature measurement appliance that are configured to detect an arranged state of the at least one protective cap. A method for operating the temperature measurement appliance includes detecting the arranged state of the protective cap on the temperature measurement appliance.