Hi there,
is it just me or can it be, that the temperature curve is not correctly simulated in MSFS? As far as i can see, the ISA deviation for example in the Citation is completely wrong. Is it probably because of this fact, that the Autopilot is unable to correctly trim the plane in Alt Hold mode? Had a chat with other users and some of them use REX Weather (SAT on the A320 suddenly at -100°C and below)which leads to a way wrong angle of attack in level flight at higher altitudes.
When I flew at 30k ft in Montana in nice and warm 40°C I opened a zen desk ticket. This was marked solved with the first weather fix. It apparently is not. Please open a ticket as well, the more the merrier. I have reopened mine too
OK, then its for sure. Had a talk to others on Facebook and the problem is easily reproduceable.
Speaking of which, just have a look here and in other places.
The weather is still a hit-and-miss for many users, especially when it comes to temperatures. Try going to KTEX and report your findings for temperature and pressure compared to real-world conditions. Yep, it‘s that far off…! 
My understanding of “Solved” means that the issue has been confirmed as a bug and your steps to reproduce have been moved into the internal bug tracking system. I do not believe it means that the bug is fixed in the next release. Opening lots of duplicate bugs is a waste of energy. You are better to change the topic to one of the types you can vote on.