El pelo rizado de mi prima se ve precioso cuando hace sol.

Both pelo and cabello can mean hair, but they are not always used in exactly the same way.

• pelo is the everyday, very common word.
• cabello can sound a bit more formal, descriptive, or literary.

In Spain, pelo rizado is completely natural for curly hair.
So El pelo rizado de mi prima... sounds normal and idiomatic.

Spanish often uses:

• definite article + noun + de + owner

So:

• el pelo de mi prima = my cousin's hair

This is very common, especially with body parts, clothes, and personal belongings.

English usually prefers a possessive structure, but Spanish often prefers this de structure. It is not more formal here; it is just normal Spanish.

Because Spanish normally keeps the article.

So even though de mi prima already tells you whose hair it is, Spanish still says:

• el pelo de mi prima

not normally:

• pelo de mi prima

This is just a standard feature of Spanish noun phrases. English and Spanish organize possession differently.

You could say:

• Su pelo rizado se ve precioso cuando hace sol.

But su can mean:

• his
• her
• your
• their

So de mi prima is clearer. It removes ambiguity.

Also, el pelo rizado de mi prima sounds slightly fuller and more descriptive, especially if the speaker wants to focus on the hair itself.

In Spanish, adjectives usually come after the noun.

So:

• pelo rizado = curly hair
• casa grande = big house

That makes pelo rizado the normal word order.

Putting the adjective before the noun is sometimes possible in Spanish, but it usually changes the tone, emphasis, or style. Here, rizado after pelo is the natural choice.

Because precioso agrees with pelo, not with prima.

• pelo is masculine singular
• so the adjective must also be masculine singular: precioso

Even though prima is feminine, she is not the noun being described by precioso here. The sentence is saying that the hair looks beautiful.

Here se ve means looks or appears.

So:

• se ve precioso = looks beautiful

This comes from verse, which is often used to talk about how something or someone looks.

Examples:

• Te ves cansado. = You look tired.
• La ciudad se ve preciosa de noche. = The city looks beautiful at night.

The se is part of this pronominal use of the verb. It is not really reflexive in the literal English sense of sees itself.

Yes, but the meaning shifts a bit.

• se ve precioso = it looks beautiful
  Focuses on appearance, especially from the speaker’s point of view.

• es precioso = it is beautiful
  Sounds more like a general quality.

• está precioso = it looks/is beautiful right now
  Often suggests a current condition or temporary state.

In this sentence, se ve precioso cuando hace sol is especially natural because the sunlight changes how it looks.

Spanish often uses pelo in the singular to mean hair as a whole, just like English can.

So:

• el pelo rizado = curly hair

If you say pelos, you are usually talking about:

• individual hairs
• different hairs
• hair in a more countable sense

So in this sentence, singular pelo is exactly what you want.

Cuando hace sol means when it’s sunny or when the sun is out.

Spanish uses hacer in several weather expressions:

• hace calor = it’s hot
• hace frío = it’s cold
• hace viento = it’s windy
• hace sol = it’s sunny

This is just an idiomatic pattern in Spanish. You do not need to translate hacer literally as to make here.

Yes. A common alternative is:

• cuando está soleado

This also means something like when it’s sunny.

But cuando hace sol is very common and very natural in everyday Spanish. In this sentence, it works especially well because it evokes the effect of sunlight on the hair’s appearance.

Prima means female cousin.

Spanish distinguishes gender here:

• primo = male cousin
• prima = female cousin

So mi prima is specifically my female cousin.