A l'hivern acostumem a portar jersei i abric quan fa vent.

Catalan often uses a with the seasons, so a l'hivern means in winter.

Here, the definite article is el, but before a word starting with a vowel, el becomes l'. So:

• a + el hivern does not stay that way
• it becomes a l'hivern

So the apostrophe shows that the e of el has disappeared.

Acostumem a + infinitive means we usually / we tend to / we are in the habit of doing something.

So:

• acostumem a portar = we usually wear / we tend to wear

A very useful contrast is:

• acostumar a + infinitive = to usually do something
• acostumar-se a = to get used to something

So in this sentence, it is about habit, not about becoming accustomed.

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

Here:

• acostumem ends in -em
• that ending shows we

So nosaltres is unnecessary unless you want extra emphasis or contrast.

Yes. Portar can mean to carry / to bring, but it is also a very common verb meaning to wear.

In Catalan, for clothes and accessories, portar is often the most natural everyday choice:

• portar un jersei = to wear a sweater
• portar ulleres = to wear glasses

So in this sentence, portar clearly means to wear, not to carry.

Because the sentence is speaking in a general, habitual way, not about one specific sweater and one specific coat.

Bare nouns are common in Catalan when talking about things people generally wear, eat, drink, or use.

So:

• portar jersei i abric = to wear sweater and coat in a general sense
• portar un jersei i un abric = to wear a specific sweater and a specific coat

The version in your sentence sounds more like a general winter habit.

Because the idea is one of each kind of garment, used generically.

Catalan often uses the singular in this kind of general statement:

• portar jersei = to wear a sweater / sweater-type clothing
• portar abric = to wear a coat

If you made them plural, it would sound more like talking about multiple sweaters and multiple coats, which is not the intended idea here.

Fa vent is the normal Catalan way to say it’s windy.

Catalan uses fer in many weather expressions:

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

English uses a dummy subject it, but Catalan usually does not. So there is no separate word for it here.

Literally, quan means when, but in a sentence about habitual actions like this one, it often has the sense of whenever.

So here it means something like:

• when / whenever it’s windy

Because the whole sentence is about what people usually do in winter, quan naturally gets that repeated, habitual meaning.

Yes. Catalan word order is fairly flexible.

This sentence puts the time expression first:

• A l'hivern acostumem a portar jersei i abric quan fa vent.

But you could also say:

• Quan fa vent, a l'hivern acostumem a portar jersei i abric.

That version puts more focus on the weather condition first. The meaning stays basically the same, though the emphasis changes slightly.

Both are masculine singular nouns.

So if you use the definite article, they are:

• el jersei
• l'abric

And with the indefinite article:

• un jersei
• un abric

You see l'abric because el becomes l' before a vowel, just like in l'hivern.