There is no one-size-fits-all answer to this question, but there are a few key indicators that can help you determine your skin's undertone. Firstly, think about how your skin reacts to the sun. Do you burn easily or do you tan? If you tend to tan more than burn, you probably have a cool skin undertone. However, if you tend to burn and then become golden-chocolate toned, you might have a warm skin undertone.
Secondly, check your veins. Look at the inside of your wrist in natural light and see how the color of your veins looks. If they have a blue or purple tint, you likely have cool skin undertones. If they have a greenish tint, you may have warm or neutral skin undertones.
Another way to check your undertone is by holding a piece of white paper up to your face. If the paper makes your skin look yellowish, you have warm skin. If it makes your skin look pinkish, you have a cool tone.
Lastly, try wearing some silver or gold jewelry and see how it complements your skin. If the silver jewelry looks more flattering, you have a cool skin undertone. If the gold jewelry looks better, you have a warm skin undertone. If neither of them stands out, you have a neutral undertone. You can also test out various makeup shades and see how they look on your skin. If a shade looks too pink, orange or yellow, it's likely warm, while if a shade looks too gray or blue, it's likely cool.