Well they are cold-blooded. They need to have the same temp. inside the cage as they do outside, would it feel good to go from a nice 80 degrees to a cold 30 degrees? Wouldn't for me.
Pay attention to the temps and wind outside. I am waiting for a sunny day with low winds at 70 degrees. I live in the high desert though, so as soon as the sun starts going down, I will pull him back inside. Hope this helps.