Operating temperature

An operating temperature is the allowable temperature range of the local ambient environment at which an electrical or mechanical device operates. The device will operate effectively within a specified temperature range which varies based on the device function and application context, and ranges from the minimum operating temperature to the maximum operating temperature (or peak operating temperature). Outside this range of safe operating temperatures the device may fail.

It is one component of reliability engineering.

Similarly, biological systems have a viable temperature range, which might be referred to as an "operating temperature".