Si fa molta calor, no vull sortir al carrer.

In Catalan, weather and temperature are often expressed with fer.

So:

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

Literally, fa calor is something like it makes heat, but you should learn it as the normal idiomatic way to talk about hot weather.

By contrast:

• està calent usually means something is physically warm or hot, like food, water, or an object.
• calorós / calorosa means warm or affectionate, depending on context, and is not the usual way to describe the weather in this sentence.

Because calor is feminine in Catalan, so the quantity word has to agree with it.

• molt = masculine singular
• molta = feminine singular
• molts = masculine plural
• moltes = feminine plural

So:

• molta calor = a lot of heat / very hot

This is different from Spanish, where calor is masculine. That difference often confuses learners.

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

• vull already means I want
• so no vull already means I don’t want

You can add jo for emphasis:

• Jo no vull sortir al carrer. = I don’t want to go out into the street.

Without jo, the sentence sounds more neutral and natural in many contexts.

After voler (to want), Catalan normally uses another verb in the infinitive, just like English.

• vull sortir = I want to go out
• no vull sortir = I don’t want to go out

This is very similar to English want + infinitive.

Also, Catalan does not usually need a word like to between the two verbs:

• vull menjar = I want to eat
• vull dormir = I want to sleep
• vull sortir = I want to go out

Sortir basically means to go out, to leave, or to come out, depending on context.

In this sentence, sortir means to go out from inside to outside.

So:

• no vull sortir = I don’t want to go out

It is broader than English leave. For example:

• surto de casa = I leave home / I go out of the house
• sortim aquesta nit = we’re going out tonight
• el sol surt = the sun comes out / rises

Al is the contraction of a + el.

• a = to / at / into
• el = the
• a + el = al

So:

• al carrer = to the street / out into the street

In this sentence, sortir al carrer means going outside, out onto the street. It often has the practical sense of going outside rather than focusing literally on the road itself.

Compare:

• sortir de casa = to leave the house
• sortir al carrer = to go out into the street / outside

In Catalan, basic negation is formed by putting no before the conjugated verb.

• vull = I want
• no vull = I don’t want

So:

• No vull sortir al carrer. = I don’t want to go out into the street.

Catalan can also use negative words like mai (never) or res (anything / nothing, depending on structure), but in this sentence simple no is enough.

Yes. That is completely natural.

Both are correct:

• Si fa molta calor, no vull sortir al carrer.
• No vull sortir al carrer si fa molta calor.

The difference is mainly focus:

• Starting with Si fa molta calor puts the condition first.
• Starting with No vull sortir al carrer puts the main statement first.

Both sound normal in everyday Catalan.

Catalan often uses the present tense in si clauses for real or likely conditions, just like English can do.

• Si fa molta calor, no vull sortir al carrer.
• If it’s very hot, I don’t want to go out.

This refers to a general situation or a real possibility.

For future meaning, Catalan still commonly uses the present after si:

• Si demà fa molta calor, no sortiré.
• If it’s very hot tomorrow, I won’t go out.

So after si, Catalan usually does not use the future tense in this kind of sentence.

If the conditional clause comes first, a comma is normally used:

• Si fa molta calor, no vull sortir al carrer.

If the main clause comes first, the comma is often omitted:

• No vull sortir al carrer si fa molta calor.

This is very similar to English punctuation.

Vull is usually pronounced roughly like BOOL, but with a Catalan ll sound.

A few helpful points:

• v and b are usually pronounced the same in most modern Catalan varieties.
• u sounds like oo in food.
• ll is often like the lli sound in million, though pronunciation can vary by dialect.

So vull is approximately bool or byool, depending on accent and how closely you imitate Catalan pronunciation.

Carrer means street.

In standard Central Catalan, it is roughly:

• cuh-RER

A few details:

• the first a is often reduced to a neutral vowel in many accents
• the final r is pronounced
• the stressed syllable is the last one: -rer

You do not pronounce it like English carrier. It is shorter and more crisp.

It can be both, depending on context.

Literally, it means to go out into the street. But very often it simply means to go outside, especially when talking about weather, protests, public activity, or leaving the house.

So in this sentence, an English speaker would often naturally understand it as:

• I don’t want to go outside if it’s very hot.

Even though the Catalan literally mentions the street, the real meaning is broader than that.