Learn Hardcore Croatian: Ljeti volim sunčane dane bez oblaka. - In summer I like sunny days without clouds.

The base noun is ljeto (“summer”).
From this noun, an adverbial form ljeti is made, and that is what you use to say “in summer” in a general, habitual sense.
Grammatically, in modern Croatian you just treat ljeti as an adverb of time, not as a regular case form you decline.

So in this sentence Ljeti volim… = “In summer I like…”, with ljeti acting like an English time adverb (similar to “usually”, “often”, etc., in terms of position in the sentence).

Why isn’t there a separate word for “in” before Ljeti? Could I say U ljeto volim sunčane dane… instead?

Croatian often uses special adverbial forms for seasons instead of “in + season”:

ljeti – in (the) summer
zimi – in (the) winter
u jesen / na jesen – in (the) autumn/fall
u proljeće – in (the) spring

Ljeti volim… is the most natural way to say “In summer I like…” in a general, habitual sense.

You can say U ljeto in some contexts, but it sounds:

more specific: U ljeto 2020. = “In the summer of 2020”
or a bit bookish/odd if you mean “every summer / in summer in general”.

For a general statement of preference like in your sentence, a native speaker would almost always choose Ljeti volim…, not U ljeto volim….

Why is the subject “I” (the word ja) not written? Is Ja volim sunčane dane… wrong?

Croatian is a pro‑drop language, which means subject pronouns are usually omitted when the verb ending already makes the subject clear.

The ending -im in volim clearly shows 1st person singular = “I”.
So volim on its own already means “I like / I love”.

Both are grammatically correct:

Volim sunčane dane bez oblaka. – neutral, natural
Ja volim sunčane dane bez oblaka. – also correct, but adds emphasis to “I” (e.g. in contrast to someone else: Ja volim…, ali on ne voli… – “I like…, but he doesn’t like…”).

In a normal, neutral statement like yours, you typically drop ja.

What form is volim, and when would I use volim instead of sviđa mi se?

Volim is:

the 1st person singular present tense of voljeti (“to love / to like”)
aspect: imperfective (good for habits, general preferences, ongoing states)

Use volim:

for stronger liking or emotional attachment:
- Volim more. – “I love the sea.”
for general preferences, including food, weather, activities:
- Ljeti volim sunčane dane. – “In summer I like sunny days.”

Use sviđa mi se:

literally “it is pleasing to me”, more like “I find it nice / I like it (right now)”
- Ovaj film mi se sviđa. – “I like this film.”

In your sentence, volim is perfect: it expresses a stable, general preference.

Why is it sunčane dane and not something like sunčani dani? What is going on with these endings?

The base (dictionary) forms are:

sunčan dan – “sunny day” (masculine singular)
plural nominative: sunčani dani – “sunny days”

In your sentence, sunčane dane is in the accusative plural, because it’s the direct object of volim:

volim + what? → sunčane dane
masculine noun dan in the accusative plural → dane
the adjective sunčan must agree with the noun in gender, number, and case, so it becomes:
- masculine, plural, accusative: sunčane

So:

Nominative plural (subject):
- Sunčani dani su lijepi. – “Sunny days are beautiful.”
Accusative plural (object):
- Volim sunčane dane. – “I like sunny days.”

How is sunčane related to sunce (“sun”)? Is there a pattern for forming adjectives like this?

Yes. The adjective sunčan (“sunny”) is derived from the noun sunce (“sun”).

Pattern (simplified):

noun sunce → adjective sunčan (-čan is a common adjective-forming suffix)
then you decline sunčan like any regular adjective:

Masculine singular (for dan):

N: sunčan dan
A: sunčan dan

Masculine plural:

N: sunčani dani
A: sunčane dane

So in the sentence, sunčane is just the plural accusative form of sunčan, agreeing with dane.

Why is it bez oblaka? What case is oblaka, and why does bez use that case?

Bez (“without”) always takes the genitive case in Croatian.

The noun oblak (“cloud”) declines like this (singular vs plural, main ones):

Singular:
- N: oblak
- G: oblaka
Plural:
- N: oblaci
- G: oblaka

You can see that genitive singular and genitive plural have the same form: oblaka.

In bez oblaka:

grammatically: genitive after bez
semantically: it means “without clouds” (plural), even though the form could also be genitive singular.

So bez + genitive is the rule:

bez šećera – without sugar
bez kiše – without rain
bez oblaka – without clouds

Is oblaka singular or plural here? How would I say “without a single cloud”?

Formally, oblaka can be genitive singular or genitive plural, but in this phrase bez oblaka it is understood as plural: “without (any) clouds”.

To emphasize “not even one cloud”, you can say:

bez ijednog oblaka – “without a single cloud”
bez ijednog jedinog oblaka – “without a single (solitary) cloud at all” (very emphatic)

All of these still use the genitive after bez:

bez
- (i)jednog (gen. masc. sg.) + oblaka (gen. masc. sg.)

Why is there no word for “the” in sunčane dane? How do I know if it means “sunny days” or “the sunny days”?

Croatian has no articles (no “a/an” and no “the”). The phrase sunčane dane can correspond to:

“sunny days”
“the sunny days”
even “some sunny days”, depending on context.

The definiteness is inferred from:

context and shared knowledge
sometimes word order or emphasis
sometimes demonstratives like ti, oni, ti sunčani dani (those sunny days)

In your sentence, as a general preference, sunčane dane is naturally understood as “sunny days” (in general), not specific ones.

Can I change the word order, e.g. say Volim ljeti sunčane dane bez oblaka? Does it change the meaning?

Croatian word order is more flexible than English, and all of these are grammatical:

Ljeti volim sunčane dane bez oblaka.
Volim ljeti sunčane dane bez oblaka.
Volim sunčane dane bez oblaka ljeti.

The basic meaning stays the same, but there are slight differences in emphasis and naturalness:

Ljeti volim…
- puts ljeti at the front → light emphasis on “as for the summer / in summer”
- sounds very natural for a general statement.
Volim ljeti sunčane dane…
- starts with Volim (I like) → neutral, also fine.
Volim sunčane dane bez oblaka ljeti.
- ljeti at the end feels like an afterthought: “I like sunny days without clouds – in summer.”
- still okay, but the first two are more typical.

So you can move ljeti around, but Ljeti volim… is a very natural, default choice.

How do I pronounce Ljeti volim sunčane dane bez oblaka correctly, especially lj and č?

Approximate pronunciation (stressed syllables in caps):

LJE‑ti – lj like the “lli” in “million”; tje a bit like “tye”
VO‑lim – voh-lim
SUN‑ča‑ne – SUN-cha-neh; č like “ch” in “church”
DA‑ne – DAH-neh
bez – like English “bez” in “bezel”, but short
O‑bla‑ka – OH-bla-kah

Put it together:

LJE‑ti VO‑lim SUN‑ča‑ne DA‑ne bez O‑bla‑ka.

Key points:

lj = a palatal l, similar to “ll” in “million”, not like English “ly” exactly, but close.
č = always like “ch” in “church”; never like “k” or “s”.
Vowels are short and pure: a, e, i, o, u are always pronounced (no schwa).