I'm confused, why would dark clothing benefit you? Surely it would conduct heat, if anything?
Ok, so the idea is that yes, black abosrbs light and therefore heat.
But.. The thing to remember is that your body radiates heat.
Black can therefore absorb and wick heat away from your body, leaving you cooler.
It must be loose though, so that you arent feeling the heat that the cloth gis giving off from absorbing sunlight.
It also relies on wind. I think given that hot air rises, it leaves a vaccuum of sorts for other air to polulate= wind.
Conversely, White clothing will reflect all of your infra-red light heat back at you, even if it reflects the sunlight
here is a link.
http://www.straightdope.com/columns/read/1886/does-black-clothing-keep-you-cooler