Originally Posted by
Lazyass
You will not be hotter wearing black. That's a myth. The bedouins who live in the desert wear black robes.
That's not entirely true.
The black robes worn by Bedouin differ from a bike jersey in one important way: they're
thick. That thickness insulates the wearer from the outer layer of the robes, which heat up because black absorbs heat (not just infrared, but also radiation in the visible spectrum--that's why it's black). This works if you're relatively sedentary, in 120
°F heat. But if you're active, then the insulation will prevent your body from cooling via sweating, by preventing the sweat from evaporating, which is an endothermic reaction. (NB: if you touch a white object in full sun, you'll note that it's much cooler than a black object of similar material, which is due to the fact that white objects reflect both infrared and visible-wave radiation, which is why it's white.)
Having said that, a black jersey should feel just as cool as a white jersey in the same riding conditions, assuming that you're sweating and that the two jerseys are adequately facilitating the evaporation of said sweat. But just standing around, looking cool after a ride? Black will heat you up much more quickly.