When light comes to us from the sun, we call it "white light" because it contains all the visible light spectrum colors available, those being red, orange, yellow, green, blue indigo, and violet. All these colors combine to make white light. We know this because we can take a prism...
and shine white light through it, and it will break the light up into the individual colors that make it up.
Objects that are black are absent of any of the visible light spectrum colors. So when those objects are radiated upon by light, none of the individual wave lengths are reflected. They are all absorbed, which translates to increased heat and temperature.
Conversely, items that are white or light colored, reflect most, if not all the wavelengths contained in the visible light spectrum. So they are reflected away from that object, which translates into same heat, same temperature.
So when you go outside, if it is hot, wear light-colored clothing; it will absorb less of the sun's radiation. If it is cold, wear dark-colored clothing; it will absorb more of the sun's radiation. Of course, this becomes complicated and changes if wind and tightness or looseness of clothing are factors. Just think of all the white animals with fluffy fur or feathers in the Arctic and Antarctic.