I am from Iowa so completely different climate from you, but our hot summer sun bakes the polymers out of many plastics and the cold winters can crack them after a few years. That and sliding onto icy seats in the winter made me choose cloth. Leather is OK, but I have seen too many problems over the years with plastics.
Uh..."bakes the polymers out of plastics?"
I don't think that means what you think it means.
Not only that, but I've lived in Florida, Texas, and North Carolina (i.e., plenty of brutal sun), and I've yet to see this phenomenon.
Maybe you mean the heat breaking the bonds that hold the polymer chains together, I don't know.
Although some people are hell bent, hell bent for leather...
What I was trying to point out is that our hot summers cause something to exit....
What I was trying to point out is that our hot summers cause something to exit the pleather and then a cold winter often leads to cracks in the surface material. I may have used the wrong word, but the overall effect to the material is the same, it cracks. I know our summers are not as hot as some of the extremes and our winters also are as not as cold as others but the very wide temperature swings seem to do a number on vinyl type materials in a few years. We get over 100 in the summer for a time and well below zero every winter and the vinyl materials get brittle over time.