Black is the easiest color to build a daily uniform with. Why do you think so many fashion people and rappers are so keen on the look? You'll look dressed up and super cool even when you're not trying to. The black tones don't have to exactly match, but two things are important when wearing dark colors in warm weather: fabric and fit. Cotton and linen are breathable fabrics that'll let you feel cool breezes, while a looser fitting T-shirts and button-downs ensure that if you do sweat, your clothes won't get glued to your body as a result of it.