Regnen rammer forruden, og vinduesviskeren bevæger sig hurtigere end normalt.

Regnen is the definite form of regn. In Danish, weather words are often used in the definite form when you mean the specific rain, snow, wind, etc. that is happening right now.

So here, regnen means something like the rain that is currently falling.
Using regn would sound more general and less tied to the immediate situation.

Rammer is the present tense of ramme.

Its basic meaning is hit, strike, or make contact with.
In this sentence, regnen rammer forruden means that the rain is hitting the windshield.

This verb is very common and can also be used in less physical ways, for example:

• Det rammer mig hårdt = It hits me hard / affects me strongly
• Han ramte målet = He hit the target

Because Danish very often forms compound nouns as a single word.

Forrude is made from:

• for- = front
• rude = pane / window

So forrude literally means front window/pane, and in normal usage it means windshield.

This is very typical in Danish. Where English often uses two words or a phrase, Danish often prefers one compound word.

Because forrude ends in an unstressed -e, and many Danish common-gender nouns of that type form the definite singular by adding just -n.

So:

• en rude → ruden
• en forrude → forruden

This is a normal pattern and worth getting used to.

Because the sentence contains two main clauses:

• Regnen rammer forruden
• vinduesviskeren bevæger sig hurtigere end normalt

In Danish, it is standard to put a comma between coordinated main clauses, even when they are joined by og.

So the comma is not random punctuation; it reflects the clause structure.

Vinduesviskeren is another compound noun.

It comes from:

• vindue = window
• visker = wiper

Together, vinduesvisker means window wiper, and in this context it means windshield wiper.

The -s- is a linking sound often used in Danish compounds. It does not usually have a separate meaning by itself; it just helps connect the parts naturally.

Then -en makes it definite:

• en vinduesvisker = a windshield wiper
• vinduesviskeren = the windshield wiper

Yes, in real life a car may have two wipers, but Danish can still use the singular if the speaker is thinking of:

• one particular wiper blade, or
• the wiper system as a single moving thing

So vinduesviskeren is perfectly natural here.
If you specifically wanted to talk about more than one, you could say vinduesviskerne.

Because bevæge sig is the normal reflexive expression for move in the sense of move itself / be moving.

So:

• bevæge can mean move something
• bevæge sig means move oneself / move

In this sentence, the wiper is doing the movement itself, so Danish uses sig.

This is a very important pattern:

• Han sætter bilen i gang = He starts the car
• Bilen bevæger sig = The car moves

Sig is a reflexive pronoun used for the third person in Danish.

Here it refers back to vinduesviskeren. So the idea is:

• vinduesviskeren bevæger sig = the windshield wiper moves itself / is moving

You do not normally translate sig literally every time. In many cases, English just uses a simple verb where Danish uses a reflexive form.

This is normal Danish main-clause word order.

Danish is a V2 language, which means the finite verb normally comes in the second position of a main clause.

So in:

• Vinduesviskeren = first element
• bevæger = second element

Then the rest follows:

• sig hurtigere end normalt

The first clause works the same way:

• Regnen = first element
• rammer = second element

Hurtigere is the comparative form of hurtig.

It means faster.

You will often see this pattern:

• hurtig = fast
• hurtigt = fast / quickly
• hurtigere = faster / more quickly

In Danish, the comparative form is the same whether it is functioning more like an adjective or an adverb. So hurtigere is exactly what you want after bevæger sig.

End means than in comparisons.

So:

• hurtigere end normalt = faster than normal / faster than usual

Normalt is the neuter/adverbial form of normal, and in this kind of expression Danish commonly uses normalt to mean normally or what is usual.

So the whole phrase is a very natural way to express comparison with the usual situation.

Yes. Hurtigere end sædvanligt is also correct and means faster than usual.

The difference is mainly one of style:

• end normalt is very common and straightforward
• end sædvanligt sounds a bit more formal or literary to some speakers

In everyday Danish, end normalt is extremely natural.