The operation of an outside temperature gauge depends on where the sensor is located. It has to be away from direct heat, so can't be outside the car body. And it has to be away from heat sources in the car such as the engine and turbo. Normally it's under a front wheel arch somewhere, but if dirt gets onto it will malfunction. All it does is attempt to give you a reading of the ambient temperature. That reading does not affect any part of the operation of the car.