This tiny app allows you to get the current air temperature on devices that do not have temperature sensor. It employs the battery thermometer (available virtually in every Android device) to measure the air temperature. If your device is not charging or running an application, you should most probably get a quite reliable reading.
TIP: If you get overestimated values, try to turn off the mobile data and WiFi. If you still get overestimated values, turn on airplane mode.