Has anyone had an issue with the accuracy or responsiveness of the thermometer display of the outdoor temperature?
I notice mine reading 10 to 15 below the known ambient outdoor temperature, even when the vehicle has been sitting outside more than a half hour.

 

It seems that you may have an issue there. My wife's 2014 CX-5 thermometer matches the temperature indicated by my VW-GTI within a degree since her car was new (my GTI is 2007).
It had a chance to see some cold temperatures too when we took it cross country to ND last May where it snowed our fourth day there. Our CX-5 lives out-doors 24X7.