The temperature sensor has two modes, Fahrenheit (for those of is in the Bahamas, Belize, the Cayman Islands, and the United States and its associated territories of Puerto Rico, American Somoa, and the U.S. Virgin Islands) and Celsius (for the everyone else).
Each mode operates between 0 and 99 degrees (0-99 Fahrenheit or 0-99 Celsius) and the voltage coming out of the module is proportional to the temperature reading. For example, if it is in Fahrenheit mode, a temperature of 85 degrees will result in an output of 85% power (which will be displayed as 85 on a number module set to value mode).
The actual temperature reading comes from the little black chip on the board (see image below).
Responsiveness & Accuracy:
The temperature sensor is not an instant read device. If you move it from a warm space to a very cold space (or vice versa) then it might take a minute for the temperature of the chip to equalize with its new surroundings.
In addition, heat from your circuit could alter your readings a tiny bit. The two holes in the circuit board help reduce heat transmission from the rest of the module. If you want to be extra precise, then you should add wire modules between the temp sensor and other modules. The power module and the cloudBit, for example, can get a little warm, so it is wire will help prevent these modules from affecting the readings from the temperature sensor.
littleBits are not waterproof. Please do not put the temperature sensor in your mouth to take your temperature. Plus, they taste weird so you will wish you hadn’t.