In my "donga" (where my scope is kept), if I leave the air-con off, daytime temperatures will rise to around 36 degrees. So far, I've had no problem in being able to come home, grab my gear and go out observing. No heat problems thus far, including the laminates. At the moment our overnight temperatures are still quite warm, so there's not a big temperature variation during my observing times.
If I've had the air-con on, say 22 degrees, I get fogging on both mirrors as soon as I take the scope outside. The lesson for me is that if I think I'm going out observing that night, the air-con is left off. If I forget, like last night, I make sure the air-con in the car is off and the windows are open to ensure any fogging is evaporated and the scope reaches ambient temperature by the time I reach the viewing site. Unlike most on this site, I have to ensure the scope is brought up to ambient temperatures, not the reverse.
In general, I don't believe natural heat or cold should affect the scope or optics. Yes, sudden changes in temperatures or formed moisture will. Avoid extremes, sudden changes and clearly adverse environments and your scope should provide the results and enjoyment you expect. Give it some extra care and respect, if in doubt. Better to err on the cautious side.
Cheers
Graeme