Jos minua paleltaa, vedän hupun ylös.

Because paleltaa is one of the Finnish verbs that takes the experiencer in the partitive case.

So Finnish says:

• minua paleltaa = I feel cold / I am cold
• sinua paleltaa = you feel cold
• meitä paleltaa = we feel cold

Here, minua is the partitive form of minä.

This is similar to other common patterns such as:

• minua väsyttää = I am tired
• minua janottaa = I am thirsty
• minua naurattaa = I feel like laughing

Paleltaa is an impersonal feeling/sensation verb.

That means:

• the person who feels something is not the normal subject
• the verb usually stays in 3rd person singular
• the person is marked in the partitive

So even if the meaning in English is I am cold, Finnish structures it differently.

You can think of minua paleltaa roughly as something like:

• cold affects me
• I am feeling chilled

This is why the structure may feel unusual to an English speaker.

They are very close, but not always identical in feel.

• minulla on kylmä = I am cold
• minua paleltaa = I feel cold / I feel chilled

A common nuance is:

• minulla on kylmä is the more general statement
• minua paleltaa can sound a bit more physical, like you are being chilled by the cold

In everyday speech, both are very natural.

Its basic meaning is if.

But in sentences about habits or usual reactions, English may sometimes use when more naturally. So this sentence can have the sense of:

• If I feel cold, I pull my hood up
• When I feel cold, I pull my hood up

Finnish still uses jos for that conditional idea.

Finnish often uses the present tense for:

• general truths
• repeated actions
• habits
• future situations, especially after words like jos

So Jos minua paleltaa, vedän hupun ylös does not have to mean only right now.

It can mean something like:

• If/when I feel cold, I pull my hood up
• If I get cold, I’ll pull my hood up

The Finnish present tense is broader than the English present in this kind of sentence.

Because the verb ending already tells you the subject.

• vedän = I pull
• vedät = you pull
• vetää = he/she/it pulls
• vedämme = we pull

So minä is usually unnecessary unless you want emphasis or contrast.

Compare:

• Vedän hupun ylös. = I pull my hood up.
• Minä vedän hupun ylös. = I pull my hood up. (more emphasis)

Yes. Vetää literally means to pull.

In this sentence, Finnish uses the very natural combination:

• vetää ... ylös = pull ... up

So vedän hupun ylös is exactly the kind of thing Finnish says for I pull my hood up.

English might also say I put my hood up, but Finnish often prefers the more physical idea of pulling it upward.

Because hupun is the object form used here.

More specifically, it is the singular total object, which in this kind of sentence has the form -n.

So:

• huppu = hood
• hupun = the hood, as the whole object being acted on

The idea is that the whole hood is being moved into the up position.

A rough contrast:

• vedän hupun ylös = I pull the hood up
• vedän huppua... = I am pulling at the hood / pulling the hood (more ongoing, incomplete, or partial-feeling)

You do not need to master all the object rules at once, but here hupun is the expected form.

Ylös means up.

It is an adverb showing direction or resulting position.

So:

• vetää hupun ylös = pull the hood up
• nostaa käsi ylös = raise a hand up
• katsoa ylös = look up

In this sentence, ylös works together with vedän to show the direction of the movement.

Usually, yes.

Finnish often leaves possession unstated when it is obvious from context, especially with things closely connected to the person, such as:

• clothing
• body parts
• personal items in the immediate situation

So vedän hupun ylös naturally suggests:

• I pull my hood up

If needed, Finnish can make possession more explicit, but in a sentence like this, it is often unnecessary.