full sun, 55 air temp is fine, the cham will bake to about 75-80 core temp. I would be more concerned with say 75-80 and sunny. Those temps my guys want in after about 30-45min if its full sun(my outdoor cage doesnt have shade) because they get too hot. By 85 full sun im lucky if can wash my car before they want in.
Gotta remember Madagascar and Yemen are not very hot nor very cold.