It is pretty hot even if their pen is in the shade. I did notice though that they don't have big fluffy coats like what you might see them with in the wild in the snow. They look like a regular leopard. Hopefully the shorter coat keeps them comfortable.
I imagine they grow longer hair in the winter, but Florida is still much hotter than Siberia would ever get in the summer. Were they panting quite a bit?
I've always thought having animals that aren't native to warm climates that don't swim is a bad idea. I can see keeping polar bears in warm zoos if they have access to chilled water but an Amur leopard doesn't have much of a way to stay cool. Snow leopards would be another bad idea in a zoo like Jacksonville.