Learn Hardcore Croatian: Kad pada jaka kiša, nigdje ne vidim djecu na igralištu. - When heavy rain is falling, I don’t see children anywhere on the playground.

Kad is just a shorter, more colloquial form. Kada can sound a bit more formal or careful, but grammatically they work the same way in this sentence.

Why is it pada jaka kiša and not something like je jaka kiša?

In Croatian, pasti / padati (to fall) is used for rain and snow, similar to “rain falls” in English.

Pada kiša. = It is raining. / Rain is falling.
Pada jaka kiša. = It is raining heavily. (literally: strong rain is falling)

Using je (to be) with kiša is not how you normally express “it’s raining”:

✗ Je jaka kiša. — sounds wrong in standard Croatian.
You could say Kiša je jaka. = The rain is strong, but this is describing the rain, not saying “it’s raining” in the everyday-weather sense.

So pada jaka kiša is the natural way to say it’s raining heavily.

Who is the subject of pada if there is no “it” in the Croatian sentence?

Croatian does not use a dummy subject like English “it” for weather.

English: It is raining.
Croatian: Pada kiša. (literally: rains rain / rain falls)

In Kad pada jaka kiša, the subject is understood from context as kiša (rain), which is mentioned right after the verb:

(Kiša) pada jaka kiša. → simplified to Pada jaka kiša.

Croatian often drops the subject when it’s obvious from the verb form or context. Here, the clause pada jaka kiša contains its own subject kiša, so no extra “it” is needed.

Why is it jaka kiša and not jaki kiša or something else?

Jaka is the feminine singular form of the adjective jak (strong).

The noun kiša (rain) is:

gender: feminine
number: singular
case: nominative (subject of the clause)

Adjectives in Croatian must agree with the noun in gender, number, and case. So:

jak (m.sg.) → for a masculine noun
jaka (f.sg.) → for a feminine noun like kiša
jako (n.sg.) → for a neuter noun

Therefore jaka kiša = strong rain / heavy rain is grammatically correct.

Why is there both nigdje and ne? Doesn’t that make a “double negative” like “I don’t see nowhere” in English?

Yes, it is a double negative, and in Croatian that is normal and correct.

Nigdje ne vidim djecu. = I don’t see children anywhere / I see children nowhere.

Croatian uses negative adverbs like:

nigdje = nowhere
nikad = never
nitko / niko = nobody
ništa / ništa = nothing

together with a negative verb (with ne) in the same clause:

Nigdje ne vidim djecu.
Nikad ne idem tamo. (I never go there.)
Nitko me ne zove. (Nobody calls me.)

Unlike in standard English, double negation is required, not wrong.

Can the word order around nigdje and ne vidim be changed?

The most natural, neutral version is:

Nigdje ne vidim djecu na igralištu.

Other orders are possible but change the focus or sound less natural:

Ne vidim nigdje djecu na igralištu. – pushes a bit more emphasis on nigdje (“I don’t see them anywhere at the playground”).
Ne vidim djecu nigdje na igralištu. – sounds more like “I don’t see the children anywhere on the playground”, with djecu more emphasized.

You normally keep nigdje close to the verb and keep ne immediately before the verb:

nigdje ne vidim
Not: ✗ nigdje vidim ne or ✗ ne nigdje vidim.

Why is it djecu and not djeca or djece?

All three forms exist; they are different cases of the same noun:

djeca – nominative plural (subject form): children
djecu – accusative plural (direct object): children
djece – genitive singular or plural: of (the) child(ren)

In the sentence:

ne vidim djecu → I don’t see children.

Here djeca are what you (don’t) see, so djeca is the direct object, which must be in the accusative case: djecu.

So:

Djeca se igraju. = The children are playing. (subject → nominative)
Vidim djecu. = I see the children / children. (object → accusative)

What does na igralištu mean exactly, and why not na igralište?

Both na igralištu and na igralište are possible, but they show different cases and meanings.

na igralištu = on / at the playground
- case: locative (place where something is)
- used with na when it means being somewhere (no movement):
  - Djeca su na igralištu. = The children are at the playground.
na igralište = to the playground
- case: accusative (direction / destination)
- used with na when it means movement to somewhere:
  - Idem na igralište. = I’m going to the playground.

In the given sentence, the idea is location (where you don’t see children), not movement, so the locative is correct:

… ne vidim djecu na igralištu.
= I don’t see any children at the playground.

What case is igralištu, and how do I recognize it?

Igralištu is in the locative singular.

The base noun is igralište (neuter), meaning playground. For many neuter nouns ending in -e / -o in the singular, the locative singular form ends in -u:

selo (village) → u selu (in the village)
more (sea) → na moru (at the sea)
igralište (playground) → na igralištu (at/on the playground)

The locative is almost always used with a preposition like u (in) or na (on/at) to express location.

Can I also say Kad jako pada kiša or Kad jako kiši instead of Kad pada jaka kiša?

Yes, both are possible, with slightly different nuances:

Kad jako pada kiša, nigdje ne vidim djecu na igralištu.
- literally: When rain is falling strongly…
- jako (strongly) is an adverb modifying pada (falls).
- Feels close in meaning to When it’s raining really hard…
Kad jako kiši, nigdje ne vidim djecu na igralištu.
- kišiti is a verb meaning to rain.
- jako modifies kiši (it rains).
- literally: When it rains heavily…
Kad pada jaka kiša …
- literally: When strong rain falls…
- jaka is an adjective modifying kiša (a strong rain).

All are correct and natural; they just use different ways of expressing “heavy rain” (strong rain / rain falls strongly / it rains strongly).

Does this sentence refer to a general habit (“whenever it rains heavily”) or to a specific time (“when it is raining heavily right now”)?

In this form, it most naturally expresses a general rule or habit:

Kad pada jaka kiša, nigdje ne vidim djecu na igralištu.
= Whenever it rains heavily, I never see children at the playground.

Croatian often uses the present tense to talk about general truths or repeated situations, especially with kad/kada:

Kad učim, ne slušam glazbu. = When I study, I don’t listen to music.
Kad pada snijeg, djeca se raduju. = When it snows, children are happy.

Context or adding words like uvijek (always) or obično (usually) can make the habitual meaning even clearer, but it isn’t necessary here.

Could Kad pada jaka kiša start a question instead of a statement?

On its own, Kad pada jaka kiša? can be a question:

Kad pada jaka kiša? = When does it rain heavily?

In your full sentence:

Kad pada jaka kiša, nigdje ne vidim djecu na igralištu.

the comma and the structure show it’s a subordinate clause (“when…”), not a question. Intonation also matters: it’s spoken with a falling tone, like a normal statement.

So:

With comma + second clause → when (subordinate):
Kad pada jaka kiša, nigdje ne vidim djecu… (statement)
Alone with question intonation → when? (question):
Kad pada jaka kiša? (question: “When does it rain heavily?”)