Været er ekstremt kaldt.

Vær means weather as a noun in its basic dictionary form.

Været is the definite singular form, literally the weather. In Norwegian, when talking about the weather in a general or current sense, the definite form is very common.

So:

• vær = weather
• været = the weather

In this sentence, været sounds natural because it refers to the weather as the thing being discussed right now.

Norwegian usually marks definiteness by adding an ending to the noun.

For neuter nouns like vær, the definite singular ending is often -et:

• et vær = a weather condition / a spell of weather
• været = the weather

This is one of the big differences from English. Instead of a separate article like the, Norwegian often attaches definiteness directly to the noun.

Er is the present tense of å være, which means to be.

So:

• å være = to be
• er = is / am / are

In this sentence, er links the subject været with the description ekstremt kaldt.

It works just like English is in:

• The weather is extremely cold.

Because vær is a neuter noun, and adjectives often agree with the noun they describe.

The noun is:

• et vær → neuter

So the adjective becomes:

• kald → basic form
• kaldt → neuter singular form

That is why you get:

• Været er kaldt.

This agreement also happens when the adjective comes after er. That is called a predicative adjective, but it still agrees in Norwegian.

Compare:

• En dag er kald. = A day is cold.
• Et vær er kaldt. = A weather condition is cold.

Here, ekstremt is functioning as an adverb, meaning extremely.

A very common pattern in Norwegian is that an adjective can be used as an adverb by adding -t:

• ekstrem = extreme
• ekstremt = extremely

So:

• ekstremt kaldt = extremely cold

This is similar to how English often uses -ly, but Norwegian usually does not use a special ending like -ly. Instead, many adjectives simply take -t when used adverbially.

You can tell from its job in the sentence.

In Været er ekstremt kaldt, ekstremt modifies the adjective kaldt, not the noun været. That means it is acting like an adverb.

So the structure is:

• været = subject
• er = verb
• ekstremt kaldt = description

And inside that description:

• kaldt = cold
• ekstremt = extremely

If it were describing a noun directly as an adjective, the structure would look different.

Because in Norwegian, predicative adjectives do not take a special definite ending just because the noun is definite.

After verbs like er, the adjective agrees mainly with:

• gender
• number

but not with definiteness in the same way as when an adjective comes before a noun.

So:

• Det kalde været = the cold weather
  Here the adjective is before the noun, so it takes the definite form kalde.
• Været er kaldt = the weather is cold
  Here the adjective comes after er, so it stays in the neuter singular agreement form kaldt.

That difference is very important.

Yes, it is a natural sentence.

However, in everyday speech, Norwegians might also often say:

• Det er ekstremt kaldt. = It is extremely cold.

That version is probably even more common in casual conversation when you are just commenting on the temperature.

The sentence Været er ekstremt kaldt is still correct and natural, but it sounds a bit more specifically focused on the weather as the topic.

The word order is:

• Været = subject
• er = verb
• ekstremt = adverb
• kaldt = adjective

So the pattern is basically:

subject + verb + adverb + adjective

This is very similar to English:

• The weather is extremely cold.

If you move another element to the front in Norwegian, the verb usually still stays in second position because of the V2 rule, but in this basic sentence the word order is straightforward.

A rough pronunciation guide is:

• været ≈ VEH-ret
• er ≈ air or a very short er sound, depending on dialect
• ekstremt ≈ ek-STREMT
• kaldt ≈ kaltt

A few useful notes:

• æ is a vowel sound that does not exist exactly the same way in English.
• In været, the r is pronounced differently depending on dialect.
• kaldt can be a bit tricky because of the consonant cluster at the end.

If you want to sound more natural, it helps to learn the whole sentence as one rhythm: Været er ekstremt kaldt.

Yes. That would also be correct.

• ekstremt kaldt = extremely cold
• veldig kaldt = very cold

The difference is strength:

• veldig is common and neutral
• ekstremt is stronger and more dramatic

So if you want a less intense version, Været er veldig kaldt works well.

These are two different structures.

1. Det kalde været

   • means the cold weather
   • here kalde comes before the noun
   • this is an attributive adjective

2. Været er ekstremt kaldt

   • means the weather is extremely cold
   • here kaldt comes after the verb er
   • this is a predicative adjective

This is why the adjective form changes:

• before the noun: kalde
• after er with a neuter singular subject: kaldt

That contrast is very common in Norwegian grammar.