Identify your undertone — warm or cool?
Undertone is the primary axis of seasonal color analysis. It describes the subtle warm (yellow-golden) or cool (pink-rosy) quality beneath your skin's surface. The most reliable proxy is the gold vs silver jewelry test.
Jewelry test
Hold a piece of gold jewelry and a piece of silver jewelry against your bare face in natural daylight (not warm indoor light). Stand near a window with the sun in front of you. Which metal looks more natural — as if it belongs near your skin — and which looks slightly jarring or stark?
Vein test
Look at the veins on your inner wrist in natural daylight. Blue or purple veins indicate cool undertone. Green veins indicate warm undertone. Mixed results suggest a more neutral undertone.
Sun reaction test
How does your skin react to sun exposure? If you tend to burn easily and barely tan, you lean cool. If you tan relatively easily, you lean warm. This is a secondary signal — use it to confirm, not lead.
Gold looks better + green veins + you tan → warm (Spring or Autumn). Silver looks better + blue veins + you burn → cool (Summer or Winter).