Learn Danish: Det afhænger af vejret. - It depends on the weather.

Both mean depends on and are often interchangeable. However, kommer an på is more common in everyday spoken Danish, whereas afhænger af sounds a bit more formal or written, though it is still perfectly normal to use in speech.

Why do we use the preposition af here?

The verb afhænge literally translates to hang off or hang from (at hænge means to hang). In Danish, this verb strictly pairs with the preposition af to mean depend on. You cannot use på here.

Can I follow afhænger af with a subordinate clause instead of a noun?

Yes! If you want to say It depends on whether it rains, you can say Det afhænger af, om det regner. Notice that the preposition af is kept right before the subordinate clause, and you must include a comma before om.

Why is vejret in the definite form here?

Just like in English where we say depends on the weather, Danish uses the definite ending -et to make vejret when referring to the weather as a general concept or an environmental condition we are all currently experiencing.