there is a TSB or RRT to make it register correctly, call your dealer and give him your last 8 of your vin and he can look it up.
Vehicle Issue Ambient temperature reading on the EVIS is 10-15 degrees off. There is a active fault of p0071 for Ambient Air Temperature Sensor Performance.
System or Component DTC / Error Message;Group 08 - Electrical;Normal Operating Temperature;Yes - Continuously
Recommendation Recommendation Tech to check the connector at the washer fluid bottle to see if there is washer fluid in that connector, you will need to replace the sensor at the washer fluid bottle. The solvent could be wicking down the wire to the ambient temp sensor ground wire .
Not saying this is it, but it might help