Si fa molt sol, has de portar un barret a la platja.

This is a very common weather pattern in Catalan. Fer often appears in weather expressions:

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

So fa molt sol literally looks like it makes a lot of sun, but idiomatically it just means it’s very sunny or the sun is very strong.

Catalan often uses a noun after fer in weather expressions, where English prefers it is + adjective.

Here, sol means sun or sunshine.

In the expression fa sol, it does not mean the physical sun as an object in the sky so much as sunny weather. So:

• sol = sun
• fa sol = it’s sunny

This is a fixed, very common expression.

Because si without an accent means if.

Compare:

• si = if
• sí = yes

So in Si fa molt sol..., the word is the conjunction if, not the word yes.

This accent difference is very important in Catalan.

Catalan often does not use a dummy subject like English it in weather expressions.

English says:

• If it is very sunny...

Catalan just says:

• Si fa molt sol...

That is completely normal. The verb stands on its own in this kind of expression.

Has de + infinitive is a very common way to express obligation, advice, or necessity directed at you.

• has de portar = you have to wear / you need to bring

Here:

• has = second person singular of haver
• de portar = to wear / to take / to bring

So has de portar un barret means you should / need to wear a hat.

Depending on context, this can sound like:

• a rule,
• practical advice,
• or a strong recommendation.

In standard Catalan, haver de + infinitive is the usual way to express obligation:

• has de portar = you have to wear / bring

Some speakers may also say tenir de, but that is much less standard for this meaning in modern Catalan. For learners, haver de is the form you should focus on.

So:

• has de portar = standard and very common
• tens de portar = not the usual standard choice here

Portar can cover several ideas that English splits into different verbs.

It can mean:

• to carry
• to bring
• to take
• to wear

In this sentence, portar un barret most naturally means to wear a hat or to take a hat with you. Because the context is the beach and strong sun, the practical idea is that you should have a hat on you, probably wearing it.

This is a good example of how one Catalan verb may match more than one English verb.

Un barret means a hat, so it refers to any hat, not a specific one already known to the listener.

Compare:

• un barret = a hat
• el barret = the hat

In this sentence, the speaker is giving general advice, so the indefinite article makes sense: you should wear a hat, not the hat.

A la platja means to the beach or at the beach, depending on context.

Here it works naturally with the idea of going there or being there:

• portar un barret a la platja = wear / bring a hat to the beach

Also notice:

• a + la stays a la
• but a + el becomes al

So:

• a la platja
• al parc

Yes, but the meaning changes slightly.

• Si fa molt sol... = If it’s very sunny...
• Quan fa molt sol... = When it’s very sunny...

Si presents a condition. Quan presents a situation that happens whenever that condition occurs.

In many practical contexts, both can work, but si is better if you want a clear if clause.

Because the sentence begins with a subordinate clause:

• Si fa molt sol, ...

Then comes the main clause:

• has de portar un barret a la platja

Using a comma here is normal and helps separate the condition from the result. This is similar to English:

• If it’s very sunny, you should wear a hat to the beach.

Yes. Catalan is somewhat flexible with word order.

You can also say:

• Has de portar un barret a la platja si fa molt sol.

That means the same thing: You should wear a hat to the beach if it’s very sunny.

The version with Si... first puts more emphasis on the condition.

Because Catalan often drops subject pronouns when the verb already shows who the subject is.

• has de already tells you the subject is you singular

So:

• has de portar = you have to wear / bring
• tu has de portar = possible, but usually only used for emphasis or contrast

This is very normal in Catalan.

Grammatically, it is talking to one person, because has de is singular:

• has de = you have to (singular)

But in real life, Catalan often uses the singular you for general advice, just like English:

• If it’s very sunny, you should wear a hat...

So it may be addressed to one person specifically, or it may mean anyone should do this.

Yes. Cal + infinitive is another common way to express necessity in a more general, impersonal way.

• Cal portar un barret a la platja si fa molt sol. = It is necessary / advisable to wear a hat to the beach if it’s very sunny.

The difference is:

• has de portar = more directly you have to / you should
• cal portar = more general, less directly addressed to one person

Both are natural, but the original sentence is more personal and direct.