LOL to answer this, I will quote myself from another thread:
oh dear, the survival instructor side of me has to pop out for a second: the color of your fabrics are actually a big part of it. for instance, while you may feel hotter in the short term in dark colors, the dark colors also block the UV which is what really messes you up . The desert and semi erid plains dwellers generally wear layers of light and dark, natural fabrics to keep themselves safe from the sun.
I second the layering of linnen and wool. When I go into the field for any of my outdoor excursions, I have a rather nice, extra lightweight Filson wool shirt that, combined with a moisture whicking base layer, keeps my comfort level at a good keel. Im actually much more comfortable than the guy in just a T-shirt as he is being hit with a lot more UV rays and the sun just burns him right through the cotton t-shirt. In fact, the guys running around shirtless on the battlefield are twice as likely to get heat stroke as well as a nasty sunburn. The layering allows for your bodys natural cooling mechanism, sweat, to work, as it allows it to slowly evaporate. The evaporation is what makes you cool. the guy with no shirt will feel cooler at first because of the rapid evaporation, however, he will dehydrate faster and he will be hotter because his body wont be able to keep up with the amount of heat vs sweat evaporation and he will overheat.
I guess what Im saying is that there are some very real advantages to a linnen undertunic and a light wool overtunic, say in 1/2 sleeve or 3/4 sleeves. when you belt your garb, be sure its baggy and lets plenty of air space, and most importantly drink LOTS AND LOTS of water. you will be fine, and in the process you will look better too!