Learn Hardcore Hungarian: Ha meleg az időjárás, csak könnyű ruhát veszek fel, vastag kabátot nem. - If the weather is warm, I put on only light clothes, not a thick coat.

The first version (meleg az időjárás) is slightly more common and a bit more neutral/natural in this kind of “when the weather is X” statement, but there is no strong change in meaning here. Hungarian word order is used mainly for focus and emphasis, and in this example there is no special emphasis, so both orders feel fine.

Could you also say Ha meleg van instead of Ha meleg az időjárás? Is there any difference?

Yes, Ha meleg van is very natural and even more common in everyday speech. It means “If it’s warm / if the weather is warm”.

Comparison:

Ha meleg az időjárás … – literally “If the weather is warm …”
Ha meleg van … – literally “If there is warmth …”, idiomatically “If it is warm …”

Ha meleg van is shorter, more colloquial, and what people typically say in spoken Hungarian.
Ha meleg az időjárás is a bit more explicit and formal, and it mentions időjárás (“weather”) explicitly, which can be useful for learners but is not needed for native speakers.

In English we say “If it is warm …”. Why is there no word for “it” in Ha meleg az időjárás / Ha meleg van?

Hungarian generally does not use an explicit dummy subject like English “it” for weather, time, etc.

English: It is warm.
Hungarian: Meleg van. (literally “Warm is / There is warm.”)

or:

English: The weather is warm.
Hungarian: Meleg az időjárás.

So:

In Meleg van, there is no pronoun equivalent to English “it”.
In Meleg az időjárás, the real subject is az időjárás (“the weather”).

Hungarian only uses pronouns (like ő, az) when there is a real referent (he, she, that thing), not as a purely grammatical filler like English “it” in it is raining, it is cold, it is late, etc.

Why do ruhát and kabátot end with -t? What does that mean?

The -t ending marks the accusative case in Hungarian – it shows that a noun is the direct object of a verb.

ruha → ruhát – “clothes / a dress” → “clothes / a dress” as object
kabát → kabátot – “coat” → “coat” as object

In the sentence:

könnyű ruhát veszek fel – “I put on light clothes”
vastag kabátot (nem) – “(I do not [put on]) a thick coat”

Both ruhát and kabátot answer “what?” after the verb veszek fel (“I put on what?”), so they must take the accusative -t.

What is the function of fel in veszek fel? Why not just veszek?

Fel is a verbal prefix (also called a “preverb” or igei előtag) that modifies the meaning of veszek.

veszek by itself primarily means “I take / I buy”.
felveszek / veszek fel (ruhát) means “I put on (clothes)”.

So:

ruhát veszek – normally understood as “I buy clothes” (in many contexts)
ruhát veszek fel – “I put on clothes”

The fel- prefix here adds the nuance of up / on, similar to English verbs like:

take vs put on / pick up

In Hungarian, these prefixes are very important and often change the basic meaning of the verb.

Why is the verb split as veszek fel and not felveszek here? Can I say felveszek?

Yes, you can also say:

Ha meleg az időjárás, csak könnyű ruhát felveszek, vastag kabátot nem.

Both felveszek and veszek fel are correct verb forms of felvenni.

The general rule:

In a neutral main clause, the preverb is normally in front of the verb:
- Felveszek egy kabátot. – I put on a coat.
When you have certain elements in focus position (often right before the verb), the preverb typically moves after the verb.

In our sentence:

csak könnyű ruhát veszek fel
Here csak könnyű ruhát is the focused thing (“only light clothes”), so the verb appears after it, and the preverb fel comes after the verb.

So both are possible, but csak könnyű ruhát veszek fel is very natural word order with clear focus on csak könnyű ruhát.

What exactly does csak do in this sentence? Could it go in another position?

Csak means “only / just” and limits what is being stated.

In csak könnyű ruhát veszek fel, it means:

“I only put on light clothes (and not heavy ones).”

Typical positions:

Csak könnyű ruhát veszek fel. – Only light clothes do I put on.
Könnyű ruhát veszek fel csak. – Possible, but less common and a bit stylistic.
Csak akkor veszek fel könnyű ruhát, ha meleg az időjárás. – “I only put on light clothes if the weather is warm.”

In your sentence, csak directly modifies könnyű ruhát, which is what is being restricted: it’s not “only I” or “only sometimes”, it’s specifically only light clothes.

Why is there no verb in vastag kabátot nem? What verb is understood here?

The second part vastag kabátot nem is an example of ellipsis – Hungarian often omits repeated verbs if they can be understood from context.

From the first half:

csak könnyű ruhát veszek fel – “I only put on light clothes”

The understood verb phrase for the second half is the same veszek fel:

vastag kabátot nem (veszek fel).
→ “I do not put on thick coats.”

So the full, non-elliptical version would be:

Ha meleg az időjárás, csak könnyű ruhát veszek fel, vastag kabátot nem veszek fel.

But repeating veszek fel would sound heavy and unnatural. Leaving it out is very typical and clear to a native speaker.

Why is nem placed at the very end, after vastag kabátot?

In the elliptical phrase vastag kabátot nem, the nem is negating the (understood) verb phrase that follows the object.

Think of it as:

vastag kabátot nem [veszek fel]
→ “a thick coat, (I) do not [put on].”

If you say the full version, the usual order would be:

Nem veszek fel vastag kabátot. – I do not put on a thick coat.
or with focus on the object: Vastag kabátot nem veszek fel.

In the short form, you keep vastag kabátot + nem, and the verb veszek fel is simply omitted because it was just used in the previous clause. So nem stays at the end of this little phrase, but logically it still negates “(veszek fel)”.

Why is there no article a / az before könnyű ruhát and vastag kabátot, but there is an article in az időjárás?

Az időjárás (“the weather”) almost always takes the definite article az when you talk about the weather in general situation-specific terms.

For ruhát and kabátot, the lack of article here indicates a generic / indefinite meaning:

könnyű ruhát veszek fel
→ “I put on light clothes / light clothing” (not a specific set of clothes)
vastag kabátot nem (veszek fel)
→ “I do not put on a thick coat” (not a specific coat)

Hungarian often omits the article when talking about:

things in a general, non-specific way
habitual actions: what you eat, wear, buy, etc., in general

If you add the article, the meaning becomes more specific:

a könnyű ruhát veszem fel – “I put on the light dress/clothes (that we both know about).”
a vastag kabátot nem veszem fel – “I don’t put on the thick coat (that we have in mind).”

In this sentence, we are talking generally about behavior in warm weather, so no article is needed.

What is the difference between időjárás and idő? Could I say Ha meleg az idő?

időjárás = weather
idő = time, but in some fixed expressions it can relate to weather (“weather/conditions”), for example:
- jó idő van – “The weather is good / It’s nice out.”
- rossz idő van – “The weather is bad.”

So:

Ha meleg az időjárás – literally “If the weather is warm”
Ha jó az idő – “If the weather is good”

Ha meleg az idő would be understood, but is not the most natural phrase; for warmth, people usually say:

Ha meleg van
or
Ha jó az idő (if the weather is nice).

So for learners it’s safest to use:

Ha meleg van …
or
Ha meleg az időjárás …

Does this Hungarian sentence refer to present or future? In English we would say “If the weather is warm, I’ll only put on light clothes…”

Hungarian uses the present tense with ha (“if/when”) even when English would naturally use the future:

Ha meleg az időjárás, csak könnyű ruhát veszek fel …
Literally: “If the weather is warm, I put on only light clothes …”
Natural English: “If the weather is warm, I’ll only put on light clothes …”

The same is true with Ha meleg van:

Ha meleg van, kimegyek a parkba.
→ “If it’s warm, I’ll go to the park.”

So: with ha-clauses, use present tense in Hungarian for both present and future situations; the context will make the time reference clear.

What is the difference between könnyű ruha and vékony ruha? Could I use vékony ruhát here?

Both adjectives relate to “lightness”, but they emphasize different aspects:

könnyű = “light” in terms of weight / general feel / not heavy, not thick
- könnyű ruha – light (summer) clothes, easy and comfortable, not heavy
vékony = “thin” in the physical thickness sense
- vékony ruha – thin clothes, literally made of thin material

In most contexts about weather and what you wear when it’s warm, könnyű ruha is more natural, because you are talking about clothing that feels light and suitable for warm weather.

You could say vékony ruhát veszek fel, but it slightly shifts the focus to the fabric being thin rather than the overall lightness/comfort. könnyű ruhát is the most typical phrase in this weather-related context.