Ako se sutra otopli, pijemo kavu na balkonu; ako opet zahladi, ostat ćemo unutra.

In Croatian, after ako (if), it is very common to use the present tense to talk about a future condition.

So:

• Ako se sutra otopli... = If it gets warmer tomorrow...
• Ako opet zahladi... = If it gets cold again...

This is normal Croatian structure. English often also uses the present after if: If it rains tomorrow..., not if it will rain tomorrow.

Also, both otopliti se and zahladiti are perfective verbs, so their present forms often refer to a single completed future change:

• otopli = it warms up / it gets warmer
• zahladi = it turns cold / it gets colder

So these are not “present-time” in meaning here; they are present forms used in a future conditional structure.

Because the two verbs are built differently.

• otopliti se = to get warmer / to warm up
• zahladiti = to turn cold / to become colder

In Croatian, some weather-change verbs are used with se, and some are not. Here:

• otopliti se is the standard form
• zahladiti usually appears without se

So you simply learn them as:

• otoplilo se
• zahladilo je

This se is not really reflexive in the English sense; it is just part of the verb’s usual form.

Croatian often uses the present tense to talk about a planned or expected future action, especially in everyday speech.

So:

• pijemo kavu na balkonu literally looks like we drink coffee on the balcony
• but here it means we’ll have coffee on the balcony

This gives a slightly more natural, immediate, arranged feeling, like a plan.

You could also say:

• Ako se sutra otopli, pit ćemo kavu na balkonu.

That is also correct and maybe a bit more explicitly future.

So the sentence uses:

• present in the first result clause: more like a plan
• future in the second result clause: more like a consequence or decision

Both are possible in Croatian.

Because Croatian allows some flexibility here, and the speaker can choose slightly different shades of meaning.

• pijemo kavu sounds like an intended plan
• ostat ćemo unutra sounds like a future outcome: we’ll stay inside

You could also say:

• Ako opet zahladi, ostajemo unutra.

That would also be correct, and it would sound more like a settled arrangement.

So the sentence mixes:

• present for planned future
• future for predicted result

This is stylistically natural.

Because kavu is the accusative singular of kava.

The verb piti (to drink) takes a direct object, and direct objects are usually in the accusative.

• nominative: kava = coffee
• accusative: kavu = coffee (as the thing being drunk)

So:

• Pijemo kavu. = We’re drinking / we’ll have coffee.

Because na with the locative is used for location.

Here the meaning is on the balcony / at the balcony area, so Croatian uses:

• na balkonu

Forms:

• nominative: balkon
• locative: balkonu

Compare:

• na stolu = on the table
• na terasi = on the terrace
• na balkonu = on the balcony

If there were movement toward the balcony, you would expect a different structure, such as:

• na balkon (accusative, in some contexts of motion)

But here it is location, so na balkonu is correct.

Because unutra is an adverb, meaning inside / indoors.

So:

• ostat ćemo unutra = we’ll stay inside

You do not need a preposition such as u here.

Compare:

• unutra = inside, indoors
• vani = outside

Examples:

• Ostani unutra. = Stay inside.
• Djeca su vani. = The children are outside.

If you wanted to mention a specific place, then Croatian might use u + a noun:

• ostat ćemo u kući = we’ll stay in the house

But unutra works on its own.

Opet means again.

So:

• ako opet zahladi = if it gets cold again

It suggests that the weather had already become cold before, or that cold weather is returning.

Croatian word order is flexible, so opet can move around a bit depending on emphasis:

• ako opet zahladi
• ako zahladi opet (less neutral here)
• ako se opet otopli etc.

In your sentence, opet is in a very natural position.

Yes. Croatian word order is fairly flexible, and sutra can move depending on emphasis.

The given version:

• Ako se sutra otopli...

is very natural.

You could also hear:

• Ako sutra otopli...
• Sutra, ako se otopli...

The differences are mostly about rhythm or emphasis, not core meaning.

In your sentence, se sutra otopli sounds smooth and idiomatic.

Because Croatian normally separates a subordinate conditional clause from the main clause with a comma.

So:

• Ako se sutra otopli, pijemo kavu na balkonu.
• Ako opet zahladi, ostat ćemo unutra.

This is standard punctuation.

The sentence then joins two parallel condition-result parts with a semicolon:

• first condition + result
• second condition + result

That punctuation helps readability, especially because both halves are fairly long and balanced.

The semicolon links two closely related parts that are already internally divided by commas.

Structure:

1. Ako se sutra otopli, pijemo kavu na balkonu
2. ako opet zahladi, ostat ćemo unutra

Each part already contains a comma after the ako clause. Using a semicolon makes the sentence clearer and more elegant than piling up more commas.

A full stop would also be possible:

• Ako se sutra otopli, pijemo kavu na balkonu. Ako opet zahladi, ostat ćemo unutra.

So the semicolon is mainly a punctuation/style choice.

Yes, ako is the normal word for real conditions like this.

• Ako se sutra otopli...
• Ako opet zahladi...

It introduces a real possibility.

A learner may compare it with kad (when), but that changes the nuance:

• ako = if
• kad = when

So:

• Ako se sutra otopli... = if it gets warmer tomorrow
• Kad se sutra otopli... would sound more like the speaker expects it to happen

In your sentence, ako is the natural choice because the weather change is uncertain.

Yes. Croatian often leaves out subject pronouns when the verb already shows the person and number.

Here:

• pijemo = we drink / we’ll drink
• ostat ćemo = we will stay

Because the endings already show we, there is no need to say mi.

You could add mi for emphasis:

• ... mi pijemo kavu na balkonu
• ... mi ćemo ostati unutra

But in a neutral sentence, leaving the pronoun out is more natural.

Yes, you could say something like:

• Ako sutra postane toplije...

That means if it becomes warmer tomorrow.

But it is not exactly the same in style.

• otopli is compact, idiomatic, and very natural for weather
• postane toplije is also correct, but more analytical

Likewise:

• ako opet postane hladnije is possible
• but ako opet zahladi is more idiomatic and concise

So the sentence uses the more natural weather verbs.

Aspect matters a lot in Croatian.

Here:

• otopliti se is perfective
• zahladiti is perfective
• ostati is perfective
• piti in pijemo is imperfective

Why this matters:

• perfective verbs often express a completed change or event

  • otopli = it gets warmer
  • zahladi = it turns cold
  • ostat ćemo = we will stay / end up staying

• imperfective verbs describe an action more as an activity or ongoing event

  • pijemo kavu = we drink / we are having coffee

That combination is very natural:

• a completed weather change happens
• then an activity follows

So aspect helps shape the sentence’s logic and feel.