[tomkinstinch]

It's too bad that the temperature sensor in the iPhone isn't accessible through the public API.

It has the hardware to measure temperature, but we can't use it.

(See: http://www.iclarified.com/images/news/3832/14751/14751.png )

[gregschlom]

Random guess: this may not be a full temperature sensor but just an on/off switch that is triggered when the temperature is above some limit.

[samg_]

It would require an Internet connection, but GPS + some weather API would do.

[jrockway]

Weather APIs know the indoor temperature?