This relates to ASE (on a second computer) together with FSInn (with weather disabled) and the NGX.I am heartened to see that the latest FSUIPC may finally help the winds, but my problem is the generation of implausibly warm temps at high altitude, 30C over ISA and more. ASE does report the correct temps at altitude, in its briefing, but they don't seem to be make it to FSX.I do set that in the performance page of the FMC, don't know if that is used in the flight computations. The very high temps will throw the IAS/Mach changeover point quite high, and with an aggressive cost index, you may top out and stop climbing.I have not been able to figure out which is the culprit (or what combo), but is anyone else seeing this? Any thoughts?* Orest

Is this happening while on VATSIM? I experienced a similar issue with 50*C ambient temps at FL210 and higher, turned out it was a conflict with FSInn's weather fetch and REX, turning off wx in FSInn fixed it for me.

FSinn is very famous for its high altitude high temperature bug. My bet is that you somewhere missed to fully turn off the FSinn weather.