Learn Hardcore Norwegian: Kvelden blir kjøligere enn dagen. - The evening becomes cooler than the day.

Yes. Blir highlights change or becoming (“as evening arrives, it gets cooler”), while er simply states a static comparison (“evening is cooler than the day”). Both are correct:

Kvelden blir kjøligere enn dagen. = emphasizes the transition
Kvelden er kjøligere enn dagen. = states a general fact

Why are kvelden and dagen in the definite form?

Norwegian often uses definite singular to talk about parts of the day in a generic sense (the category “evening,” “day”). Alternatives:

Kvelder (blir/er) kjøligere enn dager. (indefinite plural; also fine)
Det blir kjøligere om kvelden enn om dagen. (very natural, using time adverbials) Using bare singular indefinite (e.g., kveld) for a generic statement is not idiomatic.

Could the sentence refer to tonight rather than a general statement?

Context decides. With no context, it’s typically generic. In a weather-report context, Kvelden blir kjøligere enn dagen can mean “This evening will be cooler than the daytime (today).” Norwegian present tense often covers near-future. To be unambiguously “tonight,” use i kveld: Det blir kjøligere i kveld.

How is kjøligere formed, and what’s the superlative?

It’s the comparative of kjølig (“cool/chilly”): kjølig → kjøligere → kjøligst. You can also use analytic forms (mer/mest kjølig), but the -ere/-st forms are standard and more natural here.

Does kjøligere change for gender or number in this sentence?

No. After linking verbs like er/blir (predicative position), adjectives don’t take agreement endings. Examples:

Kvelden er kjølig.
Dagene er kjølige.
Kvelden blir kjøligere. Attributively (before a noun), they do: en kjølig kveld, de kjølige kveldene.

When do I use enn and when som in comparisons?

Use enn after comparative forms: kjøligere enn, større enn, flere enn.
Use som for equality: like kjølig som, like mange som, så kjølig som.

Is the word order correct? Why is the verb second?

Yes. Norwegian main clauses are V2: the finite verb is in second position. Here, the subject (Kvelden) is first and the verb (blir) is second. If you front something else, you still keep the verb second:

Om sommeren blir kvelden kjøligere enn dagen. (fronted adverbial → verb still second)

Pronunciation tips for kjøligere and kvelden?

kj is a front, hissy sound (voiceless palatal fricative), not English “sh/ch.”
ø is like French EU in “peu.”
In kjølig, the g is often weak or silent; it sounds roughly like “KJØ-li.”
In kvelden, the d in kveld is often very light or silent in many accents.

What’s the nuance difference between kjøligere and kaldere?

Kjøligere = cooler/chillier (milder). Kaldere = colder (harsher). Choose based on how cold you want to sound.

Can I drop the comparison and just say Kvelden blir kjøligere?

Yes. That’s a complete sentence meaning “The evening gets cooler,” without specifying “than what.” The original adds the explicit comparison to dagen.

Is it better style to match the comparison with similar phrases on both sides?

Often, yes. A symmetric version is very natural: Det blir kjøligere om kvelden enn om dagen. Your original is grammatical, but parallel om … om … reads especially smoothly.

Can I use på kvelden instead of om kvelden?

Yes. Both om kvelden and på kvelden are used to mean “in the evening(s).” Preferences vary by region and style; om is very common for habitual time expressions. Keep the preposition consistent within the same comparison.

If I compare with a pronoun, is it enn jeg or enn meg?

Both occur, but:

Elliptical comparisons typically use the object form: Han er høyere enn meg.
If a verb follows, use the subject form: Han er høyere enn jeg er. In everyday Bokmål, enn meg is most common when the verb is omitted.