Learn Hardcore Danish: Hvorfor er toget forsinket, når vejret er klart? - Why is the train delayed when the weather is clear?

når = when/whenever (present/future or general times). It can also be used for a time that is true now. Example: Jeg tager bussen, når det regner.
da = when (one specific time in the past). Example: Toget var forsinket, da det sneede i går.
hvis = if (condition). Example: Toget er forsinket, hvis det sneer.
selvom = even though/although (concession). Example: Toget er forsinket, selvom vejret er klart.

In your sentence, når marks the time context: “when the weather is clear.”

Why is there a comma before når?

Danish allows two comma systems. With the widely used “grammatical comma,” you put a comma before most subordinate clauses, including those introduced by når: ..., når vejret er klart. With the “new comma,” you can omit that comma: Hvorfor er toget forsinket når vejret er klart? Both are correct—be consistent within a text.

Why is the verb before the subject in Hvorfor er toget ...? Shouldn’t it be toget er?

Danish main clauses are V2 (verb-second). A question word like hvorfor takes first position, so the finite verb er must come second, and the subject toget comes after it: Hvorfor er toget .... This inversion is required in direct questions.

Why is there no inversion in når vejret er klart (why not når er vejret klart)?

Subordinate clauses in Danish do not follow V2. They keep normal subject–verb order: subject first, then verb. So it’s når vejret er klart, not når er vejret klart.

Could I use selvom instead of når?

Yes, but it changes the nuance.

..., når vejret er klart = “when the weather is clear” (time frame/general condition).
..., selvom vejret er klart = “even though the weather is clear” (explicit contrast).
If you want to emphasize the surprising contrast, selvom is stronger.

Can når talk about a specific moment in the past?

Not normally. For one specific time in the past, use da and past tense: Hvorfor var toget forsinket, da vejret var klart? Use når for present/future or general/habitual times.

Why is it toget and not tog?

toget is the definite form: “the train.” Danish typically uses the definite suffix when a specific, known entity is meant. tog (indefinite) would mean “a train.” In this context, you’re clearly talking about a specific train.

Why is it vejret and not just vejr?

vejr (“weather”) is usually treated as a unique, general thing in a given situation, so Danish often uses the definite form vejret (“the weather”) when making statements like “the weather is clear.”

Why does klart end with -t in vejret er klart?

Because vejret is neuter singular. Predicate adjectives agree in gender and number with the subject:

Common singular: Bilen er klar.
Neuter singular: Huset/Vejret er klart.
Plural: Bilerne/Husene er klare.

Why is it forsinket and not forsinkede after er?

Predicate adjectives agree with the subject:

Singular: Toget er forsinket. (neuter singular)
Plural: Togene er forsinkede.
Also note forsinket is a participle used adjectivally. Attributively it inflects too: et forsinket tog, en forsinket bus, de forsinkede tog.

What’s the difference between er forsinket and bliver forsinket?

er forsinket = is delayed (state/result).
bliver forsinket = is becoming/getting delayed (process).
Your sentence asks about the current state: “Why is the train delayed…?”

Can I say Toget er sent instead of Toget er forsinket?

Not typically. Use:

Toget er forsinket (the train is delayed).
Toget kom for sent (the train arrived late).
sent is an adverb and works well with a motion/arrival verb like kom.

Where would ikke go if I wanted to say “not”?

In the main clause: Hvorfor er toget ikke forsinket ...
In the når-clause: ..., når vejret ikke er klart?
In subordinate clauses, ikke comes before the verb’s non-finite parts and complements but after the subject and finite verb.

Can I front the når-clause?

Yes: Når vejret er klart, hvorfor er toget forsinket? It’s grammatical. Many speakers prefer keeping the når-clause at the end for flow: Hvorfor er toget forsinket, når vejret er klart?

Could I use mens instead of når?

You can, but it shifts the meaning slightly:

mens = “while,” focusing on simultaneity: ..., mens vejret er klart (“at the same time as”).
når = “when/whenever,” a general time frame or condition.
In most explanatory contexts like this, når (or selvom, if you want contrast) is more natural than mens.

Is there a more colloquial way to ask this?

Yes. A common paraphrase is: Hvordan kan det være, at toget er forsinket, når vejret er klart? (“How come the train is delayed when the weather is clear?”) You could also say: Hvorfor er toget forsinket, når nu vejret er klart? to add a “given that” flavor.