If the ambient temperature is 89 degrees above, below, and around the gondola, you can expect the outside air entering the gondola to cool the cabin to 89 degrees if the air is moving. Now add 8 humans and potentially sunlight as well. I'm not saying it's a dire situation or anything, but it's going to be pretty uncomfortable..and probably smelly too.
The Gondolas have a good amount of shade. I noticed that when trying to take pictures aboard. You need to use your flash if you want to make sure you don't have a lot of shadow in your photo.