Porto una jaqueta perquè fa fred al matí.

Yes. Portar is a very common verb with several related meanings, including:

• to carry
• to bring
• to wear

With clothing, portar often means to wear.

So Porto una jaqueta most naturally means I’m wearing a jacket or I wear a jacket.

In some contexts, it could also mean I’m carrying a jacket, but in this sentence, because of perquè fa fred al matí, the most natural interpretation is I’m wearing a jacket because it’s cold in the morning.

Catalan often leaves out subject pronouns because the verb ending already shows who the subject is.

• porto = I carry / I wear / I bring

So jo is not necessary.

You could say Jo porto una jaqueta if you want emphasis, for example:

• Jo porto una jaqueta, però ell no.
  I wear a jacket, but he doesn’t.

Without emphasis, leaving out jo is completely normal.

It can mean either one, depending on context.

In Catalan, the simple present often covers both:

• a general habit: I wear a jacket
• a current action/state: I’m wearing a jacket

So Porto una jaqueta perquè fa fred al matí could mean:

• I wear a jacket because it’s cold in the morning
• I’m wearing a jacket because it’s cold in the morning

Both are possible. The wider context would tell you which is intended.

Because Catalan normally uses an article with singular countable nouns in this kind of sentence.

• una jaqueta = a jacket

Saying just porto jaqueta would not be standard here.

So this works like English:

• I’m wearing a jacket
• Porto una jaqueta

Here perquè means because.

So:

• Porto una jaqueta perquè fa fred al matí.
• I wear/am wearing a jacket because it’s cold in the morning.

It introduces the reason for wearing the jacket.

This is a very common question.

• perquè = usually because
• per què = usually why or for what reason

Examples:

• Porto una jaqueta perquè fa fred.
  I wear a jacket because it’s cold.

• Per què portes una jaqueta?
  Why are you wearing a jacket?

So in your sentence, it must be perquè as one word, because it gives a reason.

Because Catalan uses fer in many weather expressions.

• fa fred = it’s cold
• fa calor = it’s hot
• fa vent = it’s windy
• fa sol = it’s sunny

This is just the normal Catalan pattern for talking about weather.

So fa fred is the natural way to say it’s cold in this sentence.

In fa fred, fred is part of a fixed weather expression. It behaves more like a noun in this structure, not like an adjective describing a noun.

So:

• fa fred = it’s cold
• fa calor = it’s hot

But fred can also be an adjective in other sentences, for example:

• un matí fred = a cold morning

So in your sentence, fred is part of the expression fa fred.

Al matí means in the morning.

It is made from:

• a
  • el = al

So literally it is something like at the morning, but the natural English translation is in the morning.

Examples:

• Treballo al matí.
  I work in the morning.

• Fa fred al matí.
  It’s cold in the morning.

Yes, sometimes it can, depending on context.

Catalan often uses the singular time expression in a general way:

• Al matí fa fred.

This can mean:

• It’s cold in the morning
• It’s cold in the mornings

If you want to know whether it is about one specific morning or mornings in general, you usually need context.

Because that is a very natural word order in Catalan.

The structure is:

• Porto una jaqueta
• perquè fa fred
• al matí

So the time expression comes after the weather clause.

But Catalan word order is fairly flexible. You could also say:

• Porto una jaqueta perquè al matí fa fred.
• Al matí porto una jaqueta perquè fa fred.

These are also possible, though the original sentence sounds very natural and straightforward.

It could in theory, because portar can mean to bring or to carry, but in this specific sentence that is less likely.

Why?

Because when the object is clothing, portar very often means to wear.

So most learners should understand this sentence as:

• I wear / am wearing a jacket because it’s cold in the morning

If the speaker wanted to make carry or bring clearer, context would usually help, or they might choose a different wording.

It could be either.

The present tense in Catalan is often used for:

• habits or routines
• present situations

So this sentence can mean:

• a habitual idea: I wear a jacket because it’s cold in the morning
• a current situation: I’m wearing a jacket because it’s cold this morning / in the morning

Context decides which meaning is intended. Without more context, both are grammatically possible.