The USB commands menu in cgminer will let you list all devices (press the L key) and hitting S and entering the ID (zero if you have only one stick) will show the device settings and stats. At present the temperature is always reported as 0, and a casual visual inspection doesn't show anythign that appears to be a thermistor. Unless the BT chip itself reports temperature, an external thermometer is your best best, because either the hardware doesn't report temperature, or cgminer as yet doesn't have instructions for querying the temperature sensor.