Kad smo već u ljetnom kinu, gledamo kratkometražni film.

Yes — kad normally means when, but in everyday Croatian it can also introduce a reason or circumstance, especially in combinations like kad već.

So in this sentence, Kad smo već u ljetnom kinu... is understood more like:

• Since we’re already at the summer/open-air cinema...
• Now that we’re already at the summer/open-air cinema...

This is very natural Croatian usage.

On its own, već often means already. Here it keeps that basic idea, but together with kad it creates the very common expression kad već, which means something like:

• since we’re already...
• seeing as we’re already...
• if we’re here anyway...

So već adds the sense that the situation is already true, and the main clause follows from that.

Yes, very much so. Kad već is a common Croatian pattern.

It often introduces the idea:

• since X is already the case, let’s/do Y

Examples:

• Kad već kuhaš, napravi i kavu.
  Since you’re already cooking, make coffee too.
• Kad već ideš u trgovinu, kupi kruh.
  Since you’re already going to the store, buy bread too.

So in your sentence, Kad smo već u ljetnom kinu, gledamo kratkometražni film has exactly that flavor.

Because u can take two different cases, depending on meaning:

• u + accusative = motion into/to
• u + locative = location in/at

Here the meaning is location: we are in/at the cinema, not moving into it. So Croatian uses the locative:

• u ljetnom kinu = in/at the summer cinema

Compare:

• Idemo u ljetno kino. = We’re going to the summer cinema.
  (motion, so accusative)
• Smo u ljetnom kinu. = We are at/in the summer cinema.
  (location, so locative)

Because both words have to match the locative singular:

• kino is a neuter singular noun
• ljetni is the adjective summer

In the locative singular:

• kino → kinu
• ljetni → ljetnom

So:

• nominative: ljetno kino
• locative: u ljetnom kinu

The adjective agrees with the noun in gender, number, and case.

Because Croatian usually does not need subject pronouns unless you want emphasis or contrast.

The verb forms already show who the subject is:

• smo = we are
• gledamo = we watch / we are watching

So mi is unnecessary here.

You could say Mi gledamo kratkometražni film, but that would sound more emphatic, like:

• We’re the ones watching the short film
• We are watching it, not someone else

Because the sentence describes a present situation.

• smo = we are
• gledamo = we watch / we are watching

Croatian present tense often covers both:

• a simple present meaning
• a present continuous meaning

So gledamo can mean:

• we watch
• we’re watching

The exact English translation depends on context, but the Croatian form is completely normal.

It is in the correct object case: accusative.

The verb gledati takes a direct object in the accusative:

• gledamo film = we’re watching a film

But here’s the important point:

For masculine inanimate singular nouns, the accusative looks the same as the nominative.

So:

• nominative: kratkometražni film
• accusative: kratkometražni film

That is why it looks unchanged.

If the noun were masculine animate, you would see a difference.

Kratkometražni means short-length, and in film vocabulary it means short or short-film.

So:

• kratkometražni film = short film

It is a standard film term. A useful opposite is:

• dugometražni film = feature-length film

So this is not just any random adjective — it is a very common cinema-related word.

Literally, yes. But in actual usage it usually means an open-air cinema or outdoor cinema, especially one operating in summer.

So depending on context, English might translate ljetno kino as:

• summer cinema
• open-air cinema
• outdoor cinema

All are possible, but culturally it often refers to an outdoor movie venue.

Because Kad smo već u ljetnom kinu is a subordinate clause placed before the main clause.

Structure:

• subordinate clause: Kad smo već u ljetnom kinu
• main clause: gledamo kratkometražni film

In Croatian, when a subordinate clause comes before the main clause, it is normally separated by a comma.

Croatian word order is flexible, but this order is the most natural for this meaning.

Starting with Kad smo već u ljetnom kinu... gives the reason/background first, and then the result:

• Since we’re already at the summer cinema, we’re watching a short film.

That makes the logic very clear.

You could rearrange things in Croatian, but it would usually change the emphasis, and some versions would sound less natural.

Because Croatian does not have articles.

So where English says:

• the summer cinema
• a short film

Croatian simply says:

• ljetno kino
• kratkometražni film

Whether the meaning is a, the, or something more general is understood from context.