В выходные мне хочется на природу.

Because хочется works differently from хочу.

• я хочу = I want
• мне хочется = I feel like, I have a desire to

With хочется, the person experiencing the feeling is put in the dative case, so я becomes мне.

So:

• Я хочу на природу = I want to go outdoors / to the countryside
• Мне хочется на природу = I feel like going outdoors / to the countryside

The version with хочется often sounds a bit softer, more like a current feeling or urge.

Хочется is a form of хотеться, which is an impersonal verb meaning to feel like, to want, or to be in the mood for.

It is called impersonal because the grammatical subject is not a normal person like я or он. Instead, Russian expresses the idea more like:

• To me, it is wanted
• or more naturally, I feel like...

That is why you get:

• мне хочется
• тебе хочется
• ему хочется
• нам хочется

The form хочется stays the same in all of these.

Because with impersonal expressions like хочется, Russian marks the experiencer in the dative.

So:

• я → мне
• ты → тебе
• он → ему
• она → ей

This is very common in Russian with feelings, states, and experiences:

• мне холодно = I’m cold
• мне нравится = I like it
• мне хочется = I feel like

English uses I, but Russian often uses something closer to to me in these structures.

After в meaning during / on, Russian often uses the accusative case to talk about time.

So выходные here is accusative plural.

In this phrase, выходные means the weekend or days off.

Compare:

• в выходные = on the weekend / during the weekend
• в будни = on weekdays

For this word, the plural accusative looks the same as the nominative: выходные.

Because Russian treats weekend as literally days off, which is plural.

The adjective выходной means day off or non-working. In the plural, выходные means days off / weekend.

So even when English says the weekend, Russian commonly uses a plural form:

• в выходные = on the weekend
• на выходные = for the weekend

This is just one of those places where Russian and English package the idea differently.

It can mean either, depending on context.

• в выходные can mean this weekend
• it can also mean on weekends / at weekends

In a standalone sentence like В выходные мне хочется на природу, it could be understood as:

• On weekends, I feel like going outdoors
• or This weekend, I feel like going outdoors

Context usually makes it clear. If someone wants to be more specific, they might say:

• в эти выходные = this weekend
• по выходным = on weekends, every weekend / habitually

So по выходным is better if you clearly mean a repeated habit.

Because на природу is the normal Russian idiom for out into nature, outdoors, or to the countryside.

Russian often uses на with destinations that are understood as surfaces, events, or certain set expressions, and на природу is simply the standard expression.

Compare:

• на природу = to the outdoors / into nature
• на море = to the seaside
• на дачу = to the dacha / country house

If you are already there, you would say:

• на природе = out in nature / outdoors

So:

• хочется на природу = feel like going outdoors
• люблю отдыхать на природе = I like relaxing outdoors

Literally, yes, природа means nature, but in this expression на природу usually means something more natural in English, such as:

• outdoors
• out into nature
• to the countryside
• out of the city for some fresh air

It usually suggests going somewhere natural: a park, forest, river, countryside, picnic spot, etc.

So it is more idiomatic than a word-for-word to nature.

Russian often leaves out a verb of motion when it is easy to understand from context.

So Мне хочется на природу literally looks like I feel like to the outdoors, but the real sense is:

• I feel like going outdoors
• I feel like going out into nature

If you want to make it explicit, you can add a verb:

• Мне хочется поехать на природу. = I feel like going out into nature / going to the countryside.
• Мне хочется выбраться на природу. = I feel like getting out into nature.

Without the verb, the sentence still sounds completely natural.

Yes, you can.

• Я хочу на природу = more direct, straightforward: I want to go outdoors
• Мне хочется на природу = softer, more like I feel like going outdoors

So the difference is mostly in tone:

• хочу = stronger, more direct desire
• хочется = more of a feeling, craving, or mood

Both are natural.

Russian word order is flexible, and starting with В выходные puts the time frame first:

• В выходные мне хочется на природу. = On the weekend, I feel like going outdoors.

This sounds natural if the speaker wants to frame the statement around when this feeling happens.

Other word orders are possible, for example:

• Мне хочется на природу в выходные.
• На природу мне хочется в выходные.

These are all understandable, but they shift emphasis slightly.

The original order is a very normal, neutral way to say it.

Yes, many speakers do say на выходных, especially in everyday speech.

Both can mean on the weekend / over the weekend:

• в выходные
• на выходных

However, в выходные is often taught as the more standard textbook form, while на выходных is more colloquial.

So for learners:

• в выходные = safe and standard
• на выходных = common in real speech

Then you would usually use на природе, not на природу.

This is the usual motion vs. location contrast:

• на природу = to the outdoors / into nature
  (direction, motion)
• на природе = outdoors / in nature
  (location)

Examples:

• Мы едем на природу. = We’re going outdoors / to the countryside.
• Мы отдыхаем на природе. = We’re relaxing outdoors.

In your sentence, на природу is used because the idea is wanting to go there.

No. Хочется is not agreeing with природа here.

It is a fixed impersonal form, roughly like it is desired / one feels like. That is why it stays хочется regardless of who feels the desire:

• мне хочется
• тебе хочется
• нам хочется

The phrase на природу is just what the person feels like doing or where they feel like going. It does not control the form хочется.