Learn Dutch: Vandaag is het wat bewolkt en kil. - Today it is somewhat cloudy and chilly.

In this lesson, we see wat acting as an adverb of degree, meaning "somewhat" or "a little". Instead of asking a question, it softens the adjectives bewolkt and kil, making the weather sound just a bit cloudy and chilly rather than intensely cold.

Why does the sentence say is het instead of het is?

Because the sentence starts with the time word Vandaag. Dutch uses the V2 rule, meaning the verb must be the second idea in the sentence. When you put a time word first, the verb (is) comes second, and the subject (het) is pushed to the third spot. This swapping is called inversion.

Could I just use koud instead of kil?

Yes, you could say wat koud, but kil adds a specific nuance. While koud just means cold, kil translates better to chilly, brisk, or a slightly damp, unpleasant cold. It can also be used to describe an emotionally cold person.

Why don't bewolkt or kil get an -e ending here?

Adjectives only get an -e added to them when they are placed directly in front of the noun they describe. Because bewolkt and kil come after the verb is to describe the subject, they are predicate adjectives and stay in their basic, uninflected form.