What is the hottest the chassis gets running load? from what I have seen about 37-40 C. As long at the ambient temperature is lower than that the Air should reach equilibrium.
Eh, I won't try to debate the rest of the other points with you. Let's just say... San Jose, CA is not the same as "most people" and leave it at that?
As for this question, this is the hottest the outside casing can get with the Air:
So in 70 - 80F, let's say average around 24C. With that, the Air only reaches 37 - 40C.
Australia is about 90 - 100F right now, let's say average around 34C. We're seeing 60C.
I think we can easily draw a conclusion as to how hot the "outside" can get at 110F.
Think it through. Look at the temperature differential from CPU to ambient since that drives heat dissipation rate (all else held identical).
Let's assume a CPU at 90C/194F and a 78F ambient, the delta is 116F.
Raise ambient to 90F and the delta is reduced by ~10% to 104F.
IMHO it's improbable that a 10% reduction in that temperature differential will have a truly noticeable effect in typical usage.
Yeah, but with a fan, you can speed up heat dissipation by improving airflow.
Also, temperature differential may be higher than you think. Please see above.