Prije polaska provjeravamo vremensku prognozu.

Because prije normally takes the genitive case in Croatian when it means before.

• dictionary form: polazak = departure
• after prije: prije polaska = before departure / before leaving

So the pattern is:

• prije + genitive

Examples:

• prije puta = before the trip
• prije ručka = before lunch
• prije polaska = before departure

Polazak is a noun, not a verb. It means departure, setting off, or leaving.

It is related to the verb poći / polaziti = to leave, to set off.

So Croatian is using a noun phrase here:

• prije polaska = before departure

English often uses a clause like before we leave, but Croatian often prefers a noun here.

Provjeravamo is the 1st person plural present tense form of provjeravati:

• ja provjeravam = I check
• ti provjeravaš = you check
• mi provjeravamo = we check

So provjeravamo means we check.

Croatian often uses the present tense for:

• habitual actions
• general statements
• things that regularly happen

So in this sentence it means something like we check the weather forecast before leaving.

Because it is the direct object of the verb provjeravamo.

The dictionary form is:

• vremenska prognoza = weather forecast

But after the verb, as the thing being checked, it goes into the accusative singular:

• provjeravamo vremensku prognozu = we check the weather forecast

Both words change because the adjective must agree with the noun:

• nominative: vremenska prognoza
• accusative: vremensku prognozu

In Croatian, adjectives agree with the noun they describe in:

• gender
• number
• case

Here:

• prognoza is feminine singular
• it is in the accusative
• so the adjective vremenska also has to become vremensku

That is why you get:

• vremenska prognoza → nominative
• vremensku prognozu → accusative

Not exactly. Vremensku comes from vremenski, an adjective meaning weather-related or meteorological in this context.

So:

• vrijeme = weather / time
• vremenski = weather-related

The phrase vremenska prognoza is the standard way to say weather forecast.

Croatian does not usually say this with just the noun vrijeme in the same way English says weather forecast.

No, Croatian word order is fairly flexible because case endings show the grammatical relationships.

The given sentence is a neutral, natural order:

• Prije polaska provjeravamo vremensku prognozu.

But you could also hear:

• Vremensku prognozu provjeravamo prije polaska.
• Provjeravamo vremensku prognozu prije polaska.

These alternatives shift the emphasis a bit, but the meaning stays basically the same.

Yes. That would also be natural.

Compare:

• prije polaska = before departure / before leaving
• prije nego krenemo = before we leave / before we set off

The difference is mainly structural:

• prije polaska uses a noun
• prije nego krenemo uses a full clause

The version with polaska is a bit more compact.

Because Croatian usually does not need the subject pronoun when it is already clear from the verb ending.

• provjeravamo already tells you the subject is we

So:

• provjeravamo = we check
• mi provjeravamo = we check

Adding mi is possible, but it usually adds emphasis or contrast:

• Mi provjeravamo vremensku prognozu, a oni ne. = We check the weather forecast, but they don’t.

Usually, provjeravamo is the better choice in this sentence.

Why?

Croatian has aspect:

• provjeravati = imperfective, ongoing/repeated/habitual
• provjeriti = perfective, completed single action

Here, provjeravamo sounds natural because the sentence describes a usual practice or general action: Before leaving, we check the weather forecast.

Provjerimo can appear in some contexts, but it would usually suggest a more one-off completed action and often depends on the larger sentence structure.

A simple approximate pronunciation for an English speaker is:

PREE-yeh POH-lahs-kah pro-vyeh-RAH-vah-moh VRYEH-men-skoo prog-NOH-zoo

A few useful notes:

• prije is roughly pree-yeh
• lj, nj, č, ć are often tricky in Croatian, but this sentence does not contain the hardest of those
• stress is not usually marked in normal writing, so learners typically pick it up by listening

If you want, you can also break it into chunks:

• Prije polaska
• provjeravamo
• vremensku prognozu

That makes it easier to say naturally.