Al final, terminé por quedarme en casa porque hacía frío.

Al final here means in the end or eventually.

In many cases, al final and finalmente can be similar, but there is a small nuance:

• al final = after considering different possibilities, this was the outcome
• finalmente = finally / eventually, often a bit more formal
• al fin = finally / at last, often with a stronger feeling of relief

So in this sentence, Al final fits well because it suggests that staying at home was the final result of the situation.

Examples:

• Al final, no fui. = In the end, I didn’t go.
• Finalmente, decidió aceptar. = Finally / In the end, he decided to accept.
• ¡Al fin llegó! = He finally arrived! / At last he arrived!

Terminar por + infinitive is a very common structure meaning:

• to end up doing something
• to finally do something after all
• sometimes to wind up doing something

So:

• terminé por quedarme en casa = I ended up staying at home

This structure often suggests that the result was not necessarily the original plan.

More examples:

• Terminó por aceptar la oferta. = He ended up accepting the offer.
• Terminaron por vender el coche. = They ended up selling the car.

Here, por is part of the expression terminar por + infinitive. You should learn it as a chunk.

Because the verb here is quedarse, not plain quedar.

Quedarse often means:

• to stay
• to remain

So:

• quedarme en casa = to stay at home

Without me, the meaning changes because quedar has other uses, such as:

• quedar con alguien = to arrange to meet someone
• quedar = to be left / to remain / to fit / to turn out

Compare:

• Me quedé en casa. = I stayed at home.
• Quedé con Ana. = I arranged to meet Ana.
• Queda café. = There’s coffee left.

So the reflexive pronoun me is necessary here.

Because quedarse en casa means to stay at home, while irse a casa means to go home.

They are different actions:

• Me quedé en casa. = I stayed at home.
• Me fui a casa. = I went home.

In your sentence, the idea is that the person did not go out; they remained at home. That is why quedarme en casa is the right choice.

En casa is the normal Spanish expression for at home or home, depending on context.

So:

• Estoy en casa. = I’m at home.
• Me quedé en casa. = I stayed at home.

Spanish usually does not say en la casa for this meaning unless you specifically mean in the house/building as a physical location.

Compare:

• Estoy en casa. = I’m at home.
• Estoy en la casa de mi abuela. = I’m in my grandmother’s house.

So in your sentence, en casa is the natural idiomatic expression.

Because hacía frío uses the imperfect, which is often used for:

• background description
• ongoing conditions
• weather at the time something happened

Here, the cold weather is the background reason for staying home.

So:

• porque hacía frío = because it was cold

If you said hizo frío, that would sound more like:

• it was cold (as a completed event/fact)
• a summary of weather conditions

Compare:

• Me quedé en casa porque hacía frío. = I stayed home because it was cold.
  
  • background condition
• Ayer hizo frío. = Yesterday it was cold.
  
  • simple statement about the weather

So the imperfect is very natural here.

Spanish commonly uses hacer for weather expressions.

So:

• hace frío = it’s cold
• hacía frío = it was cold
• hizo calor = it was hot

This is just the normal weather pattern in Spanish.

Common examples:

• Hace calor. = It’s hot.
• Hace buen tiempo. = The weather is nice.
• Hacía viento. = It was windy.

English uses it is for many of these, but Spanish often uses hacer.

Terminé is in the preterite because it refers to a completed action in the past: the person ultimately stayed home.

The speaker is presenting the decision/result as a finished event.

• terminé = I ended up / I finally did
• preterite = completed action

If you used the imperfect (terminaba), it would not fit well here because that would suggest an ongoing or repeated situation, not one completed outcome.

So:

• Al final, terminé por quedarme en casa = In the end, I ended up staying at home.

In this sentence, porque means because. It introduces the reason:

• porque hacía frío = because it was cold

This is different from por qué, which means why in questions.

Compare:

• Me quedé en casa porque hacía frío. = I stayed at home because it was cold.
• ¿Por qué te quedaste en casa? = Why did you stay at home?

A quick guide:

• porque = because
• por qué = why
• el porqué = the reason
• por que = less common combination in other structures

Yes, absolutely.

• Al final me quedé en casa porque hacía frío.
• Al final terminé por quedarme en casa porque hacía frío.

Both are correct, but the nuance is slightly different:

• me quedé en casa = I stayed at home
• terminé por quedarme en casa = I ended up staying at home

The version with terminé por emphasizes the final outcome more strongly, especially if there were other possibilities before.

So if you want a more neutral statement, use:

• Al final me quedé en casa.

If you want to stress that this was the eventual result, use:

• Al final terminé por quedarme en casa.

Yes. Spanish word order is flexible, especially with adverbial phrases like al final and porque hacía frío.

For example, these are all possible:

• Al final, terminé por quedarme en casa porque hacía frío.
• Terminé por quedarme en casa al final porque hacía frío.
• Porque hacía frío, al final terminé por quedarme en casa.

The first version is the most natural and clear in everyday use.

Putting Al final at the beginning works well because it sets up the idea of the final outcome right away.