Por culpa de la lluvia, volvimos a casa antes de tiempo.

Por culpa de means because of, but with a clearly negative idea: it suggests blame, inconvenience, or an unwanted cause.

So in this sentence, Por culpa de la lluvia is not just because of the rain in a neutral way — it is more like:

• because of the rain
• due to the rain
• thanks to the rain (but in a bad sense, not a positive one)

If you want a more neutral expression, Spanish often uses:

• a causa de
• debido a
• sometimes just por

So por culpa de la lluvia tells you the speaker sees the rain as the reason something went wrong or had to change.

Because lluvia is a feminine noun: la lluvia = the rain.

The expression is built like this:

• por culpa de
  • noun

So:

• por culpa de la lluvia
• literally: because of the fault/blame of the rain

You need de because culpa links to what caused the problem:

• la culpa de algo/alguien

Examples:

• por culpa del tráfico
• por culpa de Juan
• por culpa del viento

Volvimos is the preterite form of volver for nosotros:

• volver = to return / to go back
• volvimos = we returned / we went back

The sentence is talking about a completed action in the past: they went back home earlier than expected. That is why the preterite is used.

Conjugation here:

• yo volví
• tú volviste
• él/ella volvió
• nosotros volvimos
• vosotros volvisteis
• ellos volvieron

Because the sentence describes a finished event: at some point, we went back home early.

• volvimos = we returned / we went back (completed action)
• volvíamos = we were returning / we used to return (ongoing, habitual, or background action)

In this sentence, the speaker is not describing an ongoing situation. They are reporting a specific thing that happened.

So:

• Por culpa de la lluvia, volvimos a casa antes de tiempo.
  = A specific completed event.

If you used volvíamos, it would sound incomplete or would need more context, for example:

• Volvíamos a casa cuando empezó a llover.
  = We were going back home when it started to rain.

In Spanish, ir a casa, volver a casa, llegar a casa, etc. usually use casa without an article when it means home.

So:

• volver a casa = to go back home
• llegar a casa = to arrive home
• estar en casa = to be at home

This is very common and natural.

You would use la casa when you mean the house as a physical building, or when you want to specify it:

• Volvimos a la casa de Ana.
  = We went back to Ana’s house.
• La casa es grande.
  = The house is big.

So in your sentence, a casa means home, not just to the house.

Antes de tiempo means earlier than expected, ahead of time, or prematurely, depending on context.

In this sentence, it means they returned home sooner than planned or sooner than normal.

It is slightly different from just temprano:

• temprano = early
• antes de tiempo = before the expected/planned time

Compare:

• Volvimos temprano.
  = We came back early.
• Volvimos antes de tiempo.
  = We came back earlier than we were supposed to / earlier than expected.

So antes de tiempo carries the idea of some expected schedule or normal timing.

Yes, you could say Volvimos a casa temprano, and it would be correct. But the meaning is not exactly the same.

• temprano just says early
• antes de tiempo suggests earlier than planned, expected, or appropriate

So the original sentence sounds a little more precise. It implies that the rain forced them to return sooner than they intended.

If you say:

• Por culpa de la lluvia, volvimos a casa temprano.

that sounds natural, but slightly less specific.

Yes. Spanish allows flexible word order, especially with introductory phrases like por culpa de la lluvia.

These are all natural:

• Por culpa de la lluvia, volvimos a casa antes de tiempo.
• Volvimos a casa antes de tiempo por culpa de la lluvia.
• Volvimos por culpa de la lluvia a casa antes de tiempo. (possible, but less natural)

The original version is very natural because it puts the reason first. That gives the cause immediate emphasis.

So the first version sounds like:

• Because of the rain, we went back home early.

The comma separates the introductory phrase from the main clause:

• Por culpa de la lluvia, = introductory reason/cause
• volvimos a casa antes de tiempo = main statement

This comma is very natural in writing when the sentence starts with a longer phrase like this.

Without the comma, people would still understand it:

• Por culpa de la lluvia volvimos a casa antes de tiempo.

But with the comma, the sentence is clearer and more standard in writing.

Yes, but the tone changes.

• por la lluvia = because of the rain / due to the rain (more neutral)
• por culpa de la lluvia = because of the rain (with blame or annoyance)

Compare:

• Volvimos a casa antes de tiempo por la lluvia.
  Neutral: the rain was simply the reason.
• Volvimos a casa antes de tiempo por culpa de la lluvia.
  Negative: the rain caused a problem.

So if you want to keep the idea that the rain was an unwelcome cause, por culpa de is the better choice.

Yes. Regresamos a casa antes de tiempo is also correct.

Both verbs can mean to return / to go back:

• volver
• regresar

In everyday Spanish, volver is extremely common and often feels a bit more natural in many situations. Regresar is also standard and widely understood.

So:

• volvimos a casa = we went back home
• regresamos a casa = we returned home

The original sentence uses a very common, natural choice.

Yes: volver often appears with a when it means to return to a place.

Pattern:

• volver a
  • place

Examples:

• volver a casa
• volver al trabajo
• volver a Madrid

Be careful: volver a + infinitive can also mean to do something again:

• Volví a llamarlo.
  = I called him again.

So Spanish has two common patterns:

• volver a casa = return home
• volver a + infinitive = do something again

In your sentence, it is clearly the first one: return to home/homeward.

A typical Spain pronunciation would be roughly:

Por culpa de la lluvia, volvimos a casa antes de tiempo.

A few useful pronunciation notes:

• v in volvimos is pronounced like Spanish b. Spanish does not strongly distinguish English-style b and v.
• lluvia is usually pronounced with a y-like sound in most of Spain: roughly YOO-bya or LYOO-bya depending on the speaker.
• casa has a normal s sound.
• tiempo has a clear tye sound: TYEM-po.
• Stress:
  • culpa
  • lluvia
  • volvimos
  • casa
  • antes
  • tiempo

A rough English-friendly approximation is:

por KOOL-pa de la YOO-bya, bol-BEE-mos a KA-sa AN-tes de TYEM-po

That is only an approximation, but it can help you get started.

A helpful breakdown is:

• Por culpa de la lluvia = because of the rain / due to the rain (with a negative nuance)
• volvimos = we returned / we went back
• a casa = home
• antes de tiempo = earlier than expected / ahead of time

So the structure is:

• cause
  • main action
    • destination
      • time expression

This kind of sentence structure is very common in Spanish and is good to imitate in your own speaking and writing.