Vejret er for koldt til at sidde på terrassen.

In this sentence, for is the adverb meaning too / excessively:

for koldt = too cold

This is a very common Danish pattern:

for + adjective + til at + infinitive

So:

Vejret er for koldt til at sidde på terrassen
= The weather is too cold to sit on the terrace

Be careful: Danish for can also mean for, depending on context. But in front of an adjective, it often means too.

Because vejret is a neuter noun.

The noun is:

• et vejr = a weather / weather condition
• vejret = the weather

When an adjective is used after er and describes a neuter singular noun, it usually takes -t:

• Vejret er koldt = The weather is cold
• Huset er stort = The house is big

Compare with a common-gender noun:

• Dagen er kold = The day is cold

So koldt agrees with vejret.

Danish often uses the definite form when talking about weather in a general way:

• vejret = the weather

So Vejret er koldt is the normal way to say The weather is cold.

Using vejr without the definite ending would sound incomplete here. In this sentence, Danish treats the weather as a known/general condition, so vejret is the natural form.

til at sidde means to sit, but in this structure it is part of the pattern:

for + adjective + til at + verb

This corresponds to English too + adjective + to + verb.

Examples:

• for træt til at arbejde = too tired to work
• for sent til at ringe = too late to call
• for koldt til at sidde på terrassen = too cold to sit on the terrace

So til at sidde tells us what it is too cold to do.

Because this is the normal Danish construction.

After for + adjective, Danish uses:

til at + infinitive

So:

• for svært til at forstå = too difficult to understand
• for dyrt til at købe = too expensive to buy

You cannot normally drop either one here.
English uses just to sit, but Danish needs til at sidde in this pattern.

Because in Danish you normally sit on a terrace, balcony, bench, etc. when you mean being physically on that surface/area:

• sidde på terrassen = sit on the terrace / out on the patio
• sidde på altanen = sit on the balcony
• sidde på en stol = sit on a chair

Using i would usually suggest being inside something, so it would not fit terrassen here.

It literally means sit, but in context it often feels a bit broader, like:

• sit outside
• be sitting out there
• spend time seated on the terrace

So the sentence does not necessarily focus on the body position in a strict way. It is really about the weather being unsuitable for being out on the terrace.

Yes, absolutely.

Both are natural:

• Vejret er for koldt til at sidde på terrassen
• Det er for koldt til at sidde på terrassen

The version with vejret explicitly mentions the weather.
The version with det is often a little more conversational and corresponds closely to English It’s too cold to sit on the terrace.

The main clause has normal Danish word order:

Vejret + er + for koldt

That is:

• subject: Vejret
• verb: er
• complement: for koldt

Then comes the infinitive phrase:

til at sidde på terrassen

So the sentence is built like this:

[Subject] + [verb] + [description] + [too ... to ... phrase]

It is very straightforward for Danish.

You would usually just change er to var:

Vejret var for koldt til at sidde på terrassen.
= The weather was too cold to sit on the terrace.

Everything else stays the same.

Yes. This is a very productive pattern in Danish.

For example:

• Vejret er for varmt til at løbe.
  = The weather is too hot to run.

• Han er for træt til at arbejde.
  = He is too tired to work.

• Kaffen er for varm til at drikke.
  = The coffee is too hot to drink.

So once you know for + adjective + til at + verb, you can use it in many situations.

A practical approximation is:

VAI-ruth or VAI-uhth, depending on accent and how carefully someone speaks.

A few useful points:

• vej sounds roughly like English vie
• the r in vejret affects the following vowel
• the final -et is reduced in normal speech

Learners often hear it as something like vai-rəd. The exact pronunciation varies a bit, but the important thing is to recognize it when spoken, since vejret is extremely common in everyday Danish.