The following are the most common reasons for a device showing a wrong temperature.

  1. If you have been holding a device in your hand it can cause it to warm up noticeably. This is also true if the device has been on a warm surface or in full sunlight.
  2. If the device has recently been set up or reset it will have warmed up because of needing to work hard.
  3. When the device transmits data over WiFi this can cause it to warm up slightly. If you see a persistent 0.2-0.3ºC temperature difference this may be because the device is transmitting very frequently.

The solution to most of these problems is to keep the transmission frequency to 10 minutes or longer, and to leave the device to cool down. After about 20 minutes it should be showing the same reading.