I think once the temperature is higher than body temperature you want something that radiates the maximum amount of heat. But I've seen studies that seem to imply it doesn't matter which color you wear.
"Additionally, it has been said that black clothing works well under the sun if it was worn loosely and not clinging to the skin.".
OH! IT's bEEn SAiD!
Article may as well start, "As a large language model, ..."