98 Riv, Exterior temp wrong

Is there a way to recalibrate the exterior temperature reading? Mine seems to be wrong by 8 degrees Celsius. Where is the sensor located? Maybe it's blocked with snow or something.

The sensor is located between the front of the radiator and front grill, mounted vertically with one small screw. They cost about 15 bucks at Advanced (GP Sorensen Part #77919031) and look like the one in the pic below. When they get wet, the temp can be skewed until they dry out. Not likely, you would have that much snow inside the front grill area. No calibration allowed to the sensor itself.
http://img148.imageshack.us/img148/9487/ax27gg5.jpg