Todas las noches, cierro la ventana antes de acostarme.

Both are possible, and both can mean every night.

• todas las noches = all nights / every night
• cada noche = each night / every night

In this sentence, todas las noches sounds completely natural. It emphasizes a repeated habit over many nights.

A small grammar point:

• todas agrees with noches, which is feminine plural.
• noche is feminine, so it is toda la noche in the singular and todas las noches in the plural.

Because the verb is cerrar (to close), and it is a stem-changing verb.

In the present tense, e changes to ie in most forms:

• yo cierro
• tú cierras
• él/ella cierra
• nosotros cerramos
• vosotros cerráis
• ellos cierran

So cierro means I close.

Be careful:

• cierro = I close
• cerro without the i is not the present-tense form of cerrar

Spanish often leaves out subject pronouns because the verb ending already tells you who the subject is.

Here, cierro clearly means I close, so yo is unnecessary.

You could say:

• Todas las noches, yo cierro la ventana...

But that usually adds emphasis, contrast, or clarity, for example:

• Yo cierro la ventana, pero tú dejas la puerta abierta.

In a neutral sentence, leaving out yo is more natural.

Spanish often uses the definite article (el, la, los, las) where English would use a possessive like my or your, especially when it is obvious whose thing is being talked about.

So:

• cierro la ventana = literally I close the window
• In context, it may naturally mean I close my/the window

Spanish does not always need to say mi ventana unless ownership needs to be stressed or clarified.

For example:

• Cierro la ventana = normal, natural
• Cierro mi ventana = possible, but more explicit than necessary in many contexts

Because after the preposition de, Spanish uses an infinitive, not a conjugated verb.

The structure is:

• antes de + infinitive = before + -ing / before doing something

So:

• antes de acostarme = before going to bed

You cannot say:

• antes de me acuesto because me acuesto is a conjugated verb form, and that does not fit after de here.

The verb is acostarse, a reflexive verb meaning to go to bed.

Its infinitive is:

• acostar = non-reflexive base verb
• acostarse = reflexive infinitive

When a reflexive infinitive comes after a preposition like de, the reflexive pronoun stays attached to the infinitive:

• antes de acostarme = before going to bed

Here me means myself, matching the subject I.

Compare:

• Me acuesto = I go to bed
• Antes de acostarme = Before going to bed

No.

The correct form is:

• antes de acostarme

Why?

• With an infinitive, the reflexive pronoun is attached directly to the end: acostar + me = acostarme
• You do not separate it as acostar me
• After de, you do not place the pronoun before the infinitive as de me acostar

So the only correct option here is:

• antes de acostarme

Not exactly.

• acostarse = to go to bed
• dormirse = to fall asleep

So in this sentence:

• antes de acostarme means before I go to bed

That is different from:

• antes de dormirme = before I fall asleep

If you close the window as part of your bedtime routine, acostarme is the natural choice.

Because Spanish, like English, uses the present tense for habits and routines.

So:

• Todas las noches, cierro la ventana... means
• Every night, I close the window...

This is the habitual present.

It does not mean only right now. It can also describe what someone regularly does.

Other examples:

• Cada mañana, tomo café. = Every morning, I drink coffee.
• Siempre llegamos temprano. = We always arrive early.

The comma separates the time expression from the main clause.

• Todas las noches is setting the scene: every night
• Then the main statement follows: cierro la ventana antes de acostarme

The comma is common and natural here, especially in writing, because the sentence starts with a fronted time phrase.

You may sometimes see sentences like this without a comma in informal writing, but the comma is perfectly standard and helpful.

Yes. Spanish word order is more flexible than English, although some versions sound more natural in certain contexts.

For example, these are all possible:

• Todas las noches, cierro la ventana antes de acostarme.
• Cierro la ventana todas las noches antes de acostarme.
• Antes de acostarme, cierro la ventana todas las noches.

The first version is very natural if you want to begin with the routine time phrase every night.

The meaning stays basically the same, but the emphasis shifts slightly depending on what comes first.

Here it means every night, not just at night in a general sense.

• todas las noches = every night
• por la noche = at night / in the evening at night-time

Compare:

• Todas las noches, leo un poco. = Every night, I read a little.
• Por la noche, hace fresco. = At night, it’s cool.

So todas las noches clearly expresses repetition.

Yes. It is completely natural in Spain Spanish, and it would also be understood and sound normal in most of the Spanish-speaking world.

Nothing in the sentence is especially regional:

• cerrar
• la ventana
• antes de
• acostarme

These are all standard, widely used forms. So it works very well for Spanish from Spain and also for general standard Spanish.