I keep all my oil and car care products in my garage. I challenge anyone to find hotter garages in this country, than you'll find in the Southwest Mohave and Sonoran Deserts of Arizona. There aren't any. And I don't know of any subdivisions currently being built in Death Valley.
Add hot cars parked in them, and the temps are even hotter. I've never had a problem with oil, soaps, or waxes. I do use liquid wax because the paste will become liquid anyway, if it's sitting in a 140F garage. And it's easier to dispense it from a bottle, than from a tin. As was said, the oil in your engine goes from ambient to 200+F every time you start your car. Then back down again. If it can't take being stored in a hot garage, I sure wouldn't want it in my engine.