I lived in Bakersfield Ca for years, where it is 90-105'F+ from May to Oct.
It is a dry heat (6" annual rainfall) so that is better than high humidity;
My garage had finished walls and ceiling with some insulation, but it got pretty hot in there, > 90'F.
Most of my games seem no worse for wear, when stored in the garage or my self storage units.
I did not witness any new planking but most of the games i collect are from the 60s-80s.
But quick changes in humid and temp can do the most damage, especially to BG paint delaminating.