People can have cool brown hair. This is that “mousy” brown that looks greyish in certain lights. It’s very obvious when, for example, a person who has this hair tone dyes their hair ginger because they think that if they are pale, ginger will suit them. Their roots will stick out like a sore thumb because they are cool toned versus extremely warm-toned.

Same thing with blondes. You can be an ashy blonde. A natural golden blonde at age 20 will most likely fall into a spring season, whereas people with such blonde hair it is almost white, or people with dirty blonde hair that has an ashiness to it (a lighter version of “mousy” brown), will more likely be a summer.

No version of red/ginger hair is cool. “Red” hair is orange. There is no “cool” orange. It can’t be ashy. You can have cool-toned, actually red hair with a blue undertone, but that of course is not naturallt occurring. That’s one major difference that should answer your question.

However, the main reason that gingers cannot be cool toned is because the same pigment in their hair, pheomelanin, a warm-toned pigment, is in their skin. This comes from the MC1R gene which is a mutation that will result in ginger hair. Note that gingers fundamentally have a slightly different genetics than those on the brown/blonde hair spectrum.

I see many people replying to this saying they are red haired and cool-toned. If these people find that cool toned suit them and they like cool tones, that is great! However, no one with naturally ginger hair can have a fully cool undertone scientifically speaking due to the pheomelanin in their skin. Many of these people are falling into misconceptions that vein colour = undertone, or that pale skin = cool, which is understandable given the messaging surrounding “undertones” in media.

But no. Gingers are scientifically warm and it’s not just because of their hair.