The temp sensor is recessed in the front of the device near the battery compartment. The temperature of the device housing will effect the measured temperature. We are usually pretty careful not to let our body heat warm it in cold weather, or let the sun warm it up anytime.
I usually expect it to sample within 10 deg of actual. Considering the temperature could easily stratify that much across a canyon, I think its worthwhile to calculate how much that would effect your POI solution.
When I calculate the solution on the Gseven
ballistic program, I get a 1" POI change for that error. Its not big enough to matter. Its important to keep perspective on small values, and to really pay attention to the things that do. The same thing goes for pressure and humidity.
As an exercise, calc the POI difference from 0 and 100 percent humidity....