Mornin Guys....Anyone using digital gauges? I am and I have a question regarding accuracy.

I have both Autometer Digital in one truck, Glowshift Digital in the other. The water and trans temp gauges read 68 degrees in the morning when the trucks are first started. However, the outside air temperature is hovering around 45 degrees in the mornings. I would think the readings on the gauges would have been lower to the ambient air temp. After the trucks are driven for 20 or so minutes the temps seem to be in the correct range but I wonder if they are running 20 degrees hotter.

Here's another concern: This one concerns the coolant temp. Yesterday, I drove the truck with the Glowshift Gauges over the mountain to California. Had to go over the 8100 foot level and back.
This truck has the green coolant and the system was service last year. The factory gauges reads as it always does but the Digital shows that before I started the climb the coolant was at 188 degrees at about 6000 feet. I took the truck out of overdrive. The road is two lane winding and speed was under 30 mph to the top. When I hit 8100 feet the coolant was at 192 degrees. Shouldn't it have been hotter? Also, The truck was driven over an hour before the start of the climb. Here's the question. If I'm using the 195 degree thermostat and I read the coolant at 192 does that mean the thermostat never opened? Hard to believe. I was gone about 9 hours on this road trip and the highest the temp read was 192 degrees. That's climbing the mountain pass both ways. The thermostat had to have opened. The trans temp max was 172 degrees. EGT's never got over 850.
I haven't checked out the other truck with the Autometer Gauges. I'm just curious of the accuracy of the gauges, and, if in fact the thermostat actually does open. What would be the boil over point with our trucks with a 50/50 mix of green coolant and Rotella ELC at 50/50.........Just some thoughts....Jeff