The warming of the hands is an interesting one, I test after going for walks in the late evening but often have the opposite effect very cold hands upon return, so I now wonder what effect that has had, never thought!
Neil
My own theory is that my blood circulates slowly to my extremities, (or they simply don't use as much glucose from my blood stream).
If I'm not moving, or cold, my core blood doesn't get pushed to the extremities as much.
If I warm up, or exercise, particularly enough to break a sweat, it seems to 'replace' my high BG with a fresh lower reading.
It's fairly consistent with me, and I find I can get away with eating more carbs before exercise.
(I also did an experiment with holding freezer food, then running my hands under the hot tap, which made a change, but that could be the temperature of the blood simply altering the action of the meter reading)