Learn Hardcore Croatian: Sigurno će biti vruće, pa krećemo ranije. - It will surely be hot, so we are leaving earlier.

In this sentence, pa links the first clause to a consequence and is best read as “so” or “and so”: Sigurno će biti vruće, pa krećemo ranije. = “It will certainly be hot, so we’re leaving earlier.” It’s a mild, colloquial way to show result; less formal and less explicit than “therefore.”

Why is there a comma before pa?

Because pa is joining two independent clauses. In Croatian, you normally put a comma before pa when it connects full clauses: …, pa …. (If pa only linked words/phrases inside one clause, a comma wouldn’t be necessary.)

Why is it Sigurno će biti vruće and not Sigurno bit će vruće?

Clitic placement: the future auxiliary će must come in “second position” in the clause, i.e., right after the first stressed word/phrase. Since Sigurno is first, the correct order is Sigurno će biti vruće. Without the initial adverb, you get the common Bit će vruće.

Can I replace pa with zato, onda, or dakle?

zato (“that’s why”) makes the cause-effect explicit and a bit stronger: Sigurno će biti vruće, zato krećemo ranije.
onda (“then”) leans more to temporal sequence: “then we leave earlier.”
dakle (“so/therefore”) sounds more formal or summarizing.
All are possible; pa is the most neutral/colloquial link here.

Does sigurno mean “certainly” or “probably”?

Literally “certainly/surely.” In everyday speech it can soften to “most likely,” depending on tone and context. For unambiguous “probably,” use vjerojatno. For strong certainty, zasigurno or sigurno, sigurno in speech.

Why use present krećemo if we’re talking about the future?

Croatian often uses the present for planned or scheduled near-future actions: Sutra krećemo rano. You can also use the future: … pa ćemo krenuti ranije or … pa krenut ćemo ranije—both are correct.

Where do I put ćemo if I use the future with krenuti?

Keep the clitic ćemo in second position within its clause:

Pa ćemo krenuti ranije.
Pa krenut ćemo ranije.
Without pa: Krenut ćemo ranije. / Ranije ćemo krenuti.
Avoid placing ćemo later than second position in the clause.

Is krećemo from kretati or krenuti, and what’s the difference?

Krećemo is the present of the imperfective kretati (“to be setting off/moving,” habitual/ongoing). The perfective krenuti focuses on a single start: krenut ćemo (ranije) = “we’ll set off (earlier).” In practice, krećemo is very common for “we’re leaving (soon/then).”

Why is it vruće with no noun? Could I say vrućina instead?

Weather statements are often impersonal with a neuter predicate: (Bit) će vruće = “It will be hot.” Using the noun is also possible: Bit će vrućina (“There will be heat/it’ll be hot”), which can sound a bit more like “a spell of heat.”

Can I use toplo instead of vruće?

Yes, but it changes the meaning: toplo = warm; vruće = hot. Choose based on intensity.

What exactly is ranije comparing to? How can I make it explicit?

Ranije is the comparative adverb “earlier,” and the reference is understood from context (earlier than usual/than planned). To spell it out:

… krećemo ranije nego inače/obično.
… krećemo ranije nego što je bilo planirano.

Can I use prije instead of ranije?

Use ranije when you mean “earlier (in general).” Prije needs a reference:

As an adverb it usually takes a complement: Krećemo prije 7.
As a preposition: prije nečega (“before something”).
Saying just Krećemo prije sounds incomplete unless the reference is obvious.

Do I need to say the pronoun mi for “we”?

No. Croatian is a pro-drop language; the verb ending -emo already marks “we”: krećemo = “we’re leaving.”

Is Biće vruće acceptable?

That’s standard Serbian. In standard Croatian it’s written Bit će vruće (two words). Both are understood cross‑regionally, but stick to bit će in Croatian.