I noted similar observations with a friend's scangauge:
http://forum.ih8mud.com/80-series-tech/182779-airbox-manifold-air-temp-observations.html
what impressed me is that how fast the air got heated in such a short amount of time inside the air canister. The air temp is inside the MAF sensor so it's a very short distance from the fresh air intake inside the fender. I noted temps in the intake as hot as 40 degrees hotter than the air box temp!