Color Theory: Red Hair - Warm or Cool Undertones? Where do you fit?

Does red hair mean you have warm undertones? How do you know if you have cool undertones? Are you always bright? What if you have red in your hair? Jen discusses what to look for and to help you understand what colors will look good on you.
I know that our cool/warm is not supposed to change when we go gray, but when I had auburn red hair, I wore warm colors and gold jewelry. Now that I am gray, I wear cool colors and silver jewelry as the warm colors look terrible on me. My skin is cool by definition. For me my hair color made all the difference. So, maybe I am neutral? Not sure how to know.