Parvekkeelta näkyy järvi, kun taivas on kirkas.

Parvekkeelta is the noun parveke (balcony) in the ablative case.

The ending -lta / -ltä often means from, especially from the surface or general area of something.

So:

• parveke = balcony
• parvekkeelta = from the balcony / off the balcony

In this sentence, Parvekkeelta näkyy järvi means something like From the balcony, a lake is visible or more naturally You can see a lake from the balcony.

This is a very common Finnish way to express where something can be seen from.

Finnish often uses näkyä when English would say can see.

• nähdä = to see
• näkyä = to be visible / to be seen

So:

• Näen järven. = I see the lake.
• Järvi näkyy parvekkeelta. = The lake is visible from the balcony.

The Finnish sentence avoids naming the person who sees it. It focuses on the fact that the lake is visible. That is very natural in Finnish.

So Parvekkeelta näkyy järvi is not literally The balcony sees a lake. It means From the balcony, a lake can be seen.

Here järvi is the subject of the clause, so it is in the nominative form.

• järvi = lake

With näkyä, the thing that is visible is usually the grammatical subject:

• Järvi näkyy. = The lake is visible.
• Parvekkeelta näkyy järvi. = A/The lake is visible from the balcony.

Why not the other forms?

• järven is usually the genitive or accusative form
• järveä is usually the partitive form

Those forms would be used in different structures, especially with verbs like nähdä:

• Näen järven. = I see the lake.
• Näen järveä would generally not fit here in the same way.

So with näkyy, nominative järvi is the normal choice.

The subject is still there: it is järvi.

Finnish word order is flexible, so the subject does not have to come first.

This sentence is structured like:

• Parvekkeelta = from the balcony
• näkyy = is visible
• järvi = a/the lake

Even though järvi comes after the verb, it is still the subject, and it is singular. That is why the verb is singular too:

• Järvi näkyy. = singular subject, singular verb
• Järvet näkyvät. = plural subject, plural verb

So the verb agrees with järvi, not with the first word in the sentence.

Yes. Järvi näkyy parvekkeelta is also grammatical.

Both versions are possible:

• Parvekkeelta näkyy järvi
• Järvi näkyy parvekkeelta

The difference is mainly in emphasis and information structure.

• Parvekkeelta näkyy järvi puts emphasis first on from the balcony
• Järvi näkyy parvekkeelta starts with the lake

Finnish often places the most important setting or context first. So starting with Parvekkeelta sounds very natural if the point is what you can see from that location.

It can often be understood as either a lake or the lake, depending on context.

Finnish does not have articles like a/an/the, so bare nouns can be interpreted in different ways.

So järvi could mean:

• a lake if you are mentioning it for the first time
• the lake if both speakers already know which lake is meant

The exact meaning comes from context, not from an article.

Here kun means when.

So:

• kun taivas on kirkas = when the sky is clear

It introduces a subordinate clause that gives the condition or circumstance under which the lake is visible.

In many contexts, kun can also mean as, since, or appear in other time-related meanings, but here when is the best match.

You can think of the whole sentence as:

• From the balcony, a lake is visible when the sky is clear.

In natural English, that often means something like You can see the lake from the balcony when the sky is clear.

Taivas on kirkas is a normal and natural expression meaning the sky is clear / bright.

• taivas = sky
• kirkas = clear, bright

In weather contexts, kirkas can describe a clear sky very naturally.

Other adjectives may also be possible in some contexts, but kirkas is completely normal here. The sentence suggests that visibility depends on the weather being good and the sky being clear.

Because Finnish often does not need to mention a general you in this kind of sentence.

English commonly says:

• You can see a lake from the balcony

But Finnish often prefers a structure like:

• Parvekkeelta näkyy järvi

This avoids naming the viewer and simply states that the lake is visible from that place.

It is a very typical difference between English and Finnish:

• English often uses a person-based expression: you can see
• Finnish often uses a visibility-based expression: is visible

Taivas is in the nominative case, because it is the subject of the clause:

• taivas on kirkas = the sky is clear

Here:

• taivas = subject
• on = is
• kirkas = predicate adjective

This is a basic Finnish sentence pattern:

• X on Y = X is Y

For example:

• Sää on hyvä. = The weather is good.
• Taivas on kirkas. = The sky is clear.

Because after olla (to be), predicate adjectives are often in the nominative singular when the subject is singular.

So:

• taivas = singular subject
• kirkas = nominative singular adjective

That gives:

• Taivas on kirkas.

If the subject were plural, the adjective would usually be plural too:

• Taivaat ovat kirkkaat. = The skies are clear/bright.

So kirkas agrees with the subject in number here.

Most naturally, it describes a general or repeated situation:

• From the balcony, you can see the lake when the sky is clear.

It sounds like a general fact: under clear-sky conditions, the lake is visible from the balcony.

However, depending on context, it could also refer to a specific moment:

• Look — from the balcony, the lake is visible now that the sky is clear.

Finnish present tense often covers both general truths and present situations, just like English present tense can.

In practice, yes, it can feel close to if in English, although the actual word is when.

The sentence means that the lake is visible under a certain circumstance:

• when the sky is clear

In natural English, you might even translate the idea as:

• You can see the lake from the balcony if the sky is clear.

So grammatically it is kun = when, but semantically it can express something condition-like in this sentence.

A very natural way to understand it is:

• You can see the lake from the balcony when the sky is clear.

A more literal version is:

• From the balcony, a/the lake is visible when the sky is clear.

The Finnish sentence is quite compact and impersonal. It focuses on visibility and location rather than explicitly saying who sees the lake.