Feature cool blue, violet, silver, or green undertones.Plus, see trendy examples of cool tone hair colors in icy, pastel, and dark hues that are oh-so complimentary for your undertones! What Are Cool Tone Hair Colors? We’ll study how the color of your undertones helps determine the colors and shades that will look flattering on you. See our list of the best cool tone hair colors in this guide, along with tips for picking out the shades that work well for your skin tone and eye color. Mirroring your skin’s undertone with your hair color is the best way to flatter your complexion with a hue that truly suits you. If you have cool undertones, forget warm, golden shades – you’ll look amazing in cool tone hair colors. Cool Tone Hair Color Tips & Things to Consider.