This is purely antidotal, no scientific basis for the observation.
Our last coach had a light tan shade. Our current one has the typical black shade. While you can see through the black one much better, it does not block as much heat. On really hot days I'm also putting down the interior day shade.
The black also hides any dirt/streaks.
Jay and Peggy Monroe
"Can't take it with you..."
2011 Winnebago Journey Express
2020 Jeep Wrangler Unlimited