Es mejor resguardarse bajo la marquesina hasta que deje de llover.

Resguardarse is a reflexive infinitive meaning to take shelter, to protect oneself, or to get under cover.

• resguardar = to protect / to shelter
• resguardarse = to shelter oneself

The -se shows that the subject is doing the action for their own protection.

In this sentence, resguardarse sounds a bit more formal or descriptive than very basic options like protegerse or ponerse a cubierto.

Es mejor + infinitive is a very common Spanish structure for giving general advice or saying what is preferable.

So:

• Es mejor resguardarse... = It’s better to take shelter...

This is an impersonal structure. It does not say exactly who should do it; it means in general, or for anyone in that situation.

Other similar patterns are:

• Es bueno descansar. = It’s good to rest.
• Es importante estudiar. = It’s important to study.
• Es mejor esperar. = It’s better to wait.

Use ser here because mejor is expressing a general judgment or evaluation, not a temporary physical state.

• Es mejor = It is better
• Está mejor = He/She/It is better, usually in the sense of feeling better or improved

For example:

• Es mejor quedarse en casa. = It’s better to stay home.
• Después de descansar, está mejor. = After resting, he/she is better.

So in your sentence, Es mejor is the correct choice because the speaker is evaluating the best course of action.

In Spain, marquesina commonly means a covered structure that gives shelter, especially:

• a bus stop shelter
• a canopy
• an awning-like cover

In this sentence, bajo la marquesina suggests standing under some kind of roofed shelter to avoid the rain.

Depending on context, English translations could include:

• under the shelter
• under the canopy
• under the awning
• under the bus stop shelter

Both can be correct, but they are not always used in exactly the same way.

• bajo = under / beneath
• debajo de = underneath / below

In many cases, they are very close in meaning. But bajo often sounds a bit more direct, compact, and natural in this kind of sentence.

So:

• resguardarse bajo la marquesina = very natural
• resguardarse debajo de la marquesina = also understandable, but a little less idiomatic here

With shelter, Spanish often prefers bajo:

• bajo un techo = under a roof
• bajo un paraguas = under an umbrella
• bajo la lluvia = in the rain / under the rain

Because after hasta que, Spanish uses the subjunctive when the action has not happened yet and is seen as future.

Here, the rain has not stopped yet, so Spanish says:

• hasta que deje de llover = until it stops raining

This is a very important pattern:

• Espera hasta que llegue. = Wait until he/she arrives.
• Quédate aquí hasta que vuelva. = Stay here until he/she comes back.
• No salgas hasta que pare la lluvia. = Don’t go out until the rain stops.

If the action is already habitual or completed, the indicative may appear in other contexts, but in a sentence like this one, subjunctive is the normal choice.

Literally, deje de llover means it stops raining or more literally it ceases to rain.

This uses the structure:

• dejar de + infinitive = to stop doing something

Examples:

• dejar de fumar = to stop smoking
• dejar de hablar = to stop talking
• dejar de llover = to stop raining

So:

• hasta que deje de llover = until it stops raining

Even though there is no explicit subject, Spanish treats weather verbs like llover impersonally, similar to English it rains.

Yes. Hasta que pare de llover is also correct and natural.

Both mean until it stops raining:

• hasta que deje de llover
• hasta que pare de llover

A small nuance:

• dejar de llover focuses on the rain ceasing
• parar de llover also means it stops, and may feel slightly more everyday in some contexts

Both are widely understood. Your original sentence sounds perfectly good.

La marquesina suggests that the speaker has a specific shelter in mind, probably one that is visible or known from the situation.

Compare:

• bajo la marquesina = under the shelter/canopy
• bajo una marquesina = under a shelter/canopy

In real context, if both people can see the bus stop shelter or awning, Spanish naturally uses the article:

• Vamos a esperar bajo la marquesina.

It works just like English when referring to a specific thing already identifiable from context.

It sounds mostly neutral, but resguardarse gives it a slightly more careful or polished tone than the most everyday alternatives.

More neutral/everyday versions might be:

• Es mejor ponerse bajo la marquesina hasta que deje de llover.
• Es mejor refugiarse bajo la marquesina hasta que pare de llover.
• Mejor nos resguardamos bajo la marquesina hasta que deje de llover.

So the sentence is natural, but a learner should know that resguardarse is a bit more elevated than the simplest spoken choices.

Yes. Spanish often omits the subject when it is:

• general
• impersonal
• understood from context

In Es mejor resguardarse..., there is no explicit subject like uno, la gente, or nosotros, because the sentence means something like:

• It’s better to take shelter...
• One should take shelter...

Spanish does this very naturally.

Also, in deje de llover, there is no visible subject either, because weather verbs like llover are normally impersonal.

Yes, a speaker from Spain would understand it immediately, and it sounds natural.

That said, depending on the situation, they might also say something more conversational, such as:

• Es mejor ponerse bajo la marquesina hasta que pare de llover.
• Mejor nos ponemos bajo la marquesina hasta que deje de llover.
• Vamos a resguardarnos bajo la marquesina hasta que deje de llover.

Your original sentence is correct and idiomatic; it just sounds a little more polished than the most casual spoken version.