Die klimgradering wys hoe moeilik die klimroete is.

Because die is the Afrikaans definite article, meaning the.

In this sentence, there are two separate nouns:

• die klimgradering = the climbing grade/rating
• die klimroete = the climbing route

So each noun phrase gets its own die.

A useful thing to remember: Afrikaans uses die for:

• singular nouns
• plural nouns
• all genders

So it is much simpler than languages that have different forms for the.

Klimgradering is a compound noun.

It is made from:

• klim = climb / climbing
• gradering = grading / rating

Together, klimgradering means something like climbing grade or climbing rating.

Afrikaans forms compounds very often, just like English does with words such as bedroom, toothbrush, or climbing route. When reading Afrikaans, it is very helpful to look for smaller familiar pieces inside longer words.

Yes. Klimroete is another compound noun:

• klim = climb / climbing
• roete = route

So klimroete means climbing route.

This is very natural in Afrikaans. Instead of using lots of little connecting words, Afrikaans often combines nouns into one longer word.

Wys is the present-tense verb form of wys = show.

Afrikaans verbs are much simpler than English verbs:

• ek wys = I show
• jy wys = you show
• hy/sy wys = he/she shows
• ons wys = we show
• hulle wys = they show

Notice that the verb usually does not change for different subjects. English adds -s in he shows, but Afrikaans just keeps wys.

So:

• Die klimgradering wys ... = The climbing grade shows ...

This is because hoe moeilik die klimroete is is a subordinate clause.

Afrikaans often sends the verb to the end of a subordinate clause. That is why is comes last.

Structure:

• hoe = how
• moeilik = difficult
• die klimroete = the climbing route
• is = is

So literally, the pattern is:

how difficult the climbing route is

This is actually very close to English, except that Afrikaans is stricter about putting the verb at the end in subordinate clauses.

Compare:

• Main clause: Die klimroete is moeilik.
• Subordinate clause: ... hoe moeilik die klimroete is.

Because the part after wys is not a new main sentence; it is an embedded clause introduced by hoe.

In Afrikaans, subordinate clauses typically place the finite verb at the end.

So:

• Main clause: Die klimgradering wys ...
• Subordinate clause: hoe moeilik die klimroete is

This is one of the most important word-order patterns in Afrikaans.

You will see the same thing after words like:

• dat = that
• omdat = because
• as = if/when
• terwyl = while

Example:

• Ek weet dat die klimroete moeilik is.

Because moeilik is being used after a linking verb (is), not directly before a noun.

Compare:

• Die klimroete is moeilik.
  Here moeilik is a predicative adjective, so it stays plain.

• Die moeilike klimroete
  Here moeilike comes before the noun, so it usually takes -e.

This is similar to the difference between:

• The route is difficult
• The difficult route

So in your sentence, moeilik is correct because it belongs with is:

• die klimroete is moeilik

Here hoe means how.

It introduces a clause that explains the degree of difficulty:

• hoe moeilik = how difficult

So the sentence is saying that the climbing grade shows how difficult the climbing route is.

This use of hoe is very common:

• Ek weet hoe laat dit is. = I know what time it is.
• Sy verduidelik hoe dit werk. = She explains how it works.

Yes, often you could.

Both wys and toon can mean show, but wys is very common and everyday.
In many contexts:

• Die klimgradering wys hoe moeilik die klimroete is.
• Die klimgradering toon hoe moeilik die klimroete is.

Both are understandable.

Very roughly:

• wys can feel more neutral and common
• toon can sometimes sound a bit more formal or descriptive

But in a sentence like this, wys is completely natural.

A few pronunciation points may help:

• die is usually pronounced roughly like dee
• wys sounds somewhat like English vace would if it began with a w/v-like sound, but the Afrikaans y/ui sound is special and does not match English exactly
• moeilik begins with moei-, where oe sounds like oo in food
• roete has oe as well, so it sounds roughly like roo-tuh
• gradering has a rolling or guttural g sound in many accents

Two especially useful sound notes:

• oe in Afrikaans is usually like English oo
• w in Afrikaans is usually closer to English v than to English w

If you want a rough learner-friendly approximation:

• Die klimgradering wys hoe moeilik die klimroete is
• Dee klim-khrah-duh-ring vase hoo moo-uh-lik dee klim-roo-tuh is

That approximation is not perfect, but it can help as a starting point.

Yes. The sentence is in the present tense.

The verbs are:

• wys = shows
• is = is

Afrikaans often uses the simple present where English also uses the simple present:

• Die klimgradering wys ... = The climbing grade shows ...
• die klimroete is moeilik = the climbing route is difficult

So this sentence states a general fact: the climbing grade indicates the difficulty of the route.