Skiføret er i og for seg godt, men festesmøring trengs.

Skiføret is a compound noun: ski + føre.

• føre means the surface/conditions for travelling, especially on snow or roads.
• skiføre means skiing conditions.
• skiføret is the definite singular form, so literally the skiing conditions.

Norwegian forms compounds very freely, much more than English does, so putting these words together into one noun is completely normal.

Because -et marks the definite form of this neuter noun.

• et skiføre = a skiing condition / skiing conditions
• skiføret = the skiing conditions

In context, Norwegian often uses the definite form where English might use a more general expression like the ski conditions or simply conditions. It sounds natural because the speaker is referring to the actual conditions being discussed.

Because skiføret is a neuter noun.

The adjective god changes depending on gender and number:

• en-word: god
• et-word: godt
• plural/definite: gode

Since skiføre is a neuter noun (et skiføre), the predicate adjective becomes godt:

• Skiføret er godt. = The ski conditions are good.

I og for seg is an idiomatic expression meaning something like:

• in itself
• as such
• in a way
• strictly speaking
• all things considered, taken on its own

In this sentence, it softens or qualifies the statement. The speaker is saying that the skiing conditions are good in themselves, but there is still a practical issue afterward.

So the structure is roughly:

• The ski conditions are, in themselves, good, but ...

It is inserted after the verb er because it functions like a sentence adverbial/comment expression.

So:

• Skiføret er godt. = simple statement
• Skiføret er i og for seg godt. = The conditions are, in themselves, good.

This placement is very natural in Norwegian. English would often also insert the phrase in the middle:

• The ski conditions are, in themselves, good ...

Festesmøring is another compound noun:

• feste = grip/traction
• smøring = lubrication/waxing/wax

In skiing, festesmøring refers to grip wax or kick wax, the wax used so classic skis grip the snow when you push off.

So this is specialized ski vocabulary. A learner does not need to treat it as a general everyday word, but it is very common in discussions of cross-country skiing.

Because festesmøring is being used as an uncountable mass noun, like water, snow, or equipment in English.

So:

• festesmøring trengs = grip wax is needed
• not necessarily a grip wax is needed

If you wanted to refer to a specific type or a specific wax product, Norwegian could use an article in another context, but here it is talking about the substance in general.

Yes, trengs is the -s passive of trenge in this context.

• å trenge = to need
• trengs = is needed / are needed

So:

• Festesmøring trengs. = Grip wax is needed.

This -s passive is very common in Norwegian, especially in short, general statements. You could also say:

• Festesmøring er nødvendig = Grip wax is necessary
• Man trenger festesmøring = You/one need(s) grip wax

But trengs is concise and natural.

Men means but and introduces a contrast.

The speaker is balancing two ideas:

• the ski conditions are good in general
• however, grip wax is still needed

So the overall effect is:

• The conditions are basically good, but you still need grip wax.

This kind of contrast is very common with i og for seg, because that phrase often sets up a partial agreement before adding a limitation.

Yes, it strongly suggests classic cross-country skiing rather than downhill skiing or skating.

That is because festesmøring is specifically associated with getting grip under the ski for the kick phase in classic skiing. If you know that word, it tells you a lot about the situation.

So culturally and practically, this is a very Norwegian outdoors sentence: it is discussing snow conditions in a precise, experience-based way.

Not very naturally. A word-for-word translation would sound awkward in English, especially because of i og for seg and the skiing compounds.

A more natural English rendering would be something like:

• The ski conditions are good in themselves, but grip wax is needed.
• The skiing conditions are fairly good, but you need grip wax.
• The snow is good for skiing overall, but grip wax is needed.

So this is a good example of a sentence where understanding the parts helps, but idiomatic translation gives better English.