Xrhrft

A character looks at another character, skin colour creates certain associations. A character looks at himself, and associations would be shaped by society, and by what is "normal" in that society. What we refer to as "black", for example covers a huge range of brown shades, that would only be jumbled together as "black" where "white" is the "norm". "Brown" is an even more confusing category, that appears to be a catch-all for all the shades that are neither "black" nor "white". And all those distinctions are only half about actual colour, other half being things like ethnicity.

Now, I need to throw away all those weird cultural associations, and start from scratch. Both novels I am currently working on are set in the Middle East (or a fantasy version thereof), so the range of Middle-Eastern skin colours is the "norm".

I am narrating my stories in third-person, one limited, the other - omniscient. Culturally, my "narrator voice" is very much where my characters are.

Under those constraints, how do I describe my MCs' skin colour? (Other characters can sort of follow from the MC's baseline and the MC's perception.) I have so far used "tanned", but that isn't right at all - it suggests that the character is naturally paler than they currently appear, which is not what I'm trying to describe. "Brown" doesn't really work either, for the reasons explained above, and also because it's not really descriptive - so many shades of brown. And it would be strange, I think, to describe my MCs' appearance in exotic terms, since they're supposed to be pretty much the norm.

(It might be that I'm having a blind spot, because this is what I look like. Since it's mine, it's just "skin" to me.)

This question is related, but its point of reference is different, and the accepted answer has a "Houston, we have a problem" in the exact colour range that
I'm trying to describe.

Maybe relate the skintone to the person's surroundings? Example: comparing the skintone to the color of the sand nearby, or a building, and talking about "the sharp contrast" or the shared undertones. You can work in colors as needed, but basically, the idea is to use what's surrounding the character to help describe them.

I have had many friends from the Middle East and their skin tones ranged from essentially white to soft brown. I found a more telling feature that seemed to set them apart were some slight similarities in facial features.

Mention of the MC’s skin tone need not be made. Your character could notice that others are paler than he or darker than he. You could even have some horse related theme since the Arabs are culturally people of the horse.

You could have him notice that his skin is the color of one of his favourite spices.

Tea is almost a religion there, those with dark skin could be seen as resembling strong tea.

When it came to horses, darker colour ones were thought to fare worse in the sun so were eschewed.

I like to equate skin tones with food or natural objects. Caramel, chocolate, cream, sand, etc. Eye and hair color work well this way too.

There are so many beautiful shades of skin it is a shame to leave it out of descriptions. White people tend to focus on hair and eyes and ignore skin aside from the very large divisions of black and brown and white (not that anyone's skin is truly black or white). Or they mention "tanned" which implies a change from the natural color due to leisure or work in the sun.

The Black community in particular has a rich history of naming different skins, and then depicting them in written or visual art. Many other ethnic groups have gorgeous descriptions. Reading how they do it should help fuel your ideas.

People notice if you leave it out. Maybe not white people (they'd notice if you never described hair color), but certainly people from the cultures you're writing about.

In addition to comparing people's colors to natural objects, you can compare them to each other.

"Her lover's skin was translucent against hers. Cream marked with the
slightest tint of beet. Her own ebony seemed almost blue in the
morning light."

I'm going to start the answer with a question of my own:

Why do you need to describe the skin colour?

What does it actually add? Is it a core pillar of the story? Or a point of differentiation?

JK Rowling and Harry Potter are great examples of this. When Noma Dumezweni was cast as Hermione in Harry Potter and the Cursed Child there was a lot of bigoted, racist outcry.
JK Rowling set it straight in no uncertain terms. At no time did she mention that Hermione Grainger was white, or what skin tone she was. Her defining feature was her brown, wild hair and her personality. That's it.

So I would ask the same question of you. Is your MC's defining feature their skin tone? Or is it something else? Are they a part of a relatively homogenous society? If so, what is achieved by describing skin tone? Look at their other traits - are they muscular? Long haired? Close shaven scalp? Beard or clean shaven? Scars? Injuries etc. All serve to differentiate your character without having to describe what their skin tone is.

And you've touched on this yourself. They are "the norm", so you can't describe them as exotic. You yourself used the words "this is what I look like. Since it's mine, it's just "Skin" to me". This is no different for your story.