The LabQuest internal temperature sensor measures temperature inside the LabQuest case. Its calibration is adjusted to approximate ambient temperature, but can deviate depending on the battery charge state and freshly powered warm-up time.

The biggest source of error for the sensor is that when the battery is charging or discharging, the battery generates heat and this can cause the temperature sensor to read a few degrees high in still air. Even gently moving air will reduce this error significantly.

See also:
What is the difference between the microphone built into the LabQuest and the MCA-BTA microphone?