Der Balkonstuhl ist noch nass vom Regen.

Because German very often makes compound nouns by joining nouns together.

• Balkon = balcony
• Stuhl = chair

So Balkonstuhl literally means balcony chair.

This is completely normal in German. English often uses separate words, but German usually combines them into one noun.

Also, in compounds, the last noun is the main one:

• a Balkonstuhl is a kind of Stuhl
• that last part also determines the gender

The gender comes from the last part of the compound noun.

• der Stuhl = the chair
• therefore der Balkonstuhl = the balcony chair

So even though der Balkon is also masculine, what really matters here is the final part, Stuhl.

In a normal German main clause, the finite verb usually comes in position 2.

So in:

• Der Balkonstuhl = subject
• ist = verb
• noch nass vom Regen = rest of the sentence

This follows the standard German word order pattern.

If you moved another element to the front, the verb would still stay second:

• Noch ist der Balkonstuhl nass vom Regen.

Here noch means still.

So Der Balkonstuhl ist noch nass means the chair is still wet — it was wet before, and it has not dried yet.

That is a very common use of noch.

Compare:

• Er schläft noch. = He is still sleeping.
• Es ist noch kalt. = It is still cold.

Because nass is being used as a predicate adjective, not directly before a noun.

After verbs like:

• sein = to be
• werden = to become
• bleiben = to stay

German adjectives usually do not take endings.

So:

• Der Stuhl ist nass. = correct
• der nasse Stuhl = correct when the adjective comes before the noun

Compare:

• Der Balkonstuhl ist nass.
• Der nasse Balkonstuhl steht draußen.

Vom Regen means from the rain or more naturally in English, because of the rain / wet from the rain.

It explains the cause of the wetness.

So:

• nass vom Regen = wet from the rain

This is a very natural German way to say that something got wet because rain fell on it.

Vom is a contraction of von dem.

• von dem → vom

This contraction is extremely common and usually sounds more natural.

So:

• nass vom Regen is the normal form, while
• nass von dem Regen sounds much less natural in this sentence.

Because the preposition von always takes the dative.

• von + dem Regen
• contracted: vom Regen

So the case is not chosen by the noun itself; it is required by the preposition von.

Yes, but the meaning and feel are a little different.

• nass vom Regen = wet from the rain; focuses on the direct physical cause
• wegen des Regens = because of the rain; more abstract or formal

For this sentence, nass vom Regen is the most natural choice.

Compare:

• Der Balkonstuhl ist noch nass vom Regen. = The chair is still wet from the rain.
• Wegen des Regens ist der Balkonstuhl noch nass. = Because of the rain, the chair is still wet.

Both are possible, but the first sounds more natural here.

No. You could also say things like:

• Der Stuhl auf dem Balkon ist noch nass vom Regen.
• Der Stuhl auf dem Balkon ist noch nass.

These mean slightly different things:

• Balkonstuhl suggests a chair meant for balcony/outdoor use
• der Stuhl auf dem Balkon just means the chair that is located on the balcony

So Balkonstuhl is more like a type of chair, while Stuhl auf dem Balkon is just a description of where it is.

Because in German, all nouns are capitalized.

In this sentence:

• Balkonstuhl
• Regen

are capitalized because they are nouns.

This is a basic German spelling rule and helps learners identify nouns more easily.