Det var varmt i forrige uke.

It was warm last week.

Breakdown of Det var varmt i forrige uke.

• være: to be
• det: it
• varm: warm
• i forrige uke: last week

Questions & Answers about Det var varmt i forrige uke.

What is the function of det in this sentence?

It’s an expletive or “dummy” subject, much like the it in English it’s raining or it’s cold. Norwegian declarative clauses generally require a subject, so det fills that spot without referring to anything concrete.

Why is var used instead of har vært or ble?

var is the simple past (preterite) of å være (“to be”), used for a finished state at a specific time in the past (“it was warm”).

• har vært (present perfect) would emphasize a connection to the present (“it has been warm”).
• ble is the past of å bli (“to become”) and suggests a change of state (“it became warm”).

Why is the adjective varm spelled varmt here?

In Norwegian, predicative adjectives agree with the grammatical gender of their subject. Here, the subject is the neuter pronoun det, so the adjective must take its neuter singular form, which adds -t: varmt.

What is the purpose of the i before forrige uke? Can you omit it?

The preposition i marks a time frame—“in last week.” However, with many time expressions you can drop the preposition and still be correct:

• i forrige uke (“in last week”)
• forrige uke (“last week”)
  Both versions are natural, though omitting i is slightly more colloquial.

Can you start the sentence with forrige uke instead?

Yes. Norwegian follows the V2 rule (verb-second), so you can front any adverbial. You’d get:
Forrige uke var det varmt.
This is equally correct and often used for emphasis on the time frame.

What’s the difference between forrige uke and sist uke?

• forrige uke is the standard way to say “last week.”
• sist uke is common in speech but technically means “the final week” of some period. Many dialects do use sist uke to mean “last week,” but in formal writing forrige uke is preferred.

How would you ask “Was it warm last week?” in Norwegian?

By inverting the subject and verb (question word order):
Var det varmt i forrige uke?
(or Var det varmt forrige uke? without the i).