Anyone know where a garmin edge 500 gets its temperature info from? Is it a sensor mounted on the unit or satellite data? Mine this morning as I neared the end of my ride said 105.2. Now it was hot but not that bad, thermometer when I reached home said 94. Makes me think the unit must have a temp sensor and it was affected by being out in the sun, but friends say it comes from satellite. Anyone know for sure?