האוויר בחוץ קר.

A natural pronunciation is:

ha-avír ba-chúts kar

A few notes:

• האוויר = ha-avír
  The ה at the beginning is ha-, meaning the.
• בחוץ = ba-chúts
  The ח is the throaty Hebrew sound, like the ch in German Bach or Scottish loch.
• קר = kar
  Short and simple: kar.

The main stress is usually on:

• -vír in ha-avír
• -chúts in ba-chúts

Because ה is the Hebrew definite article, meaning the.

• אוויר = air
• האוויר = the air

So Hebrew is saying the air rather than just air.

This is very normal in Hebrew. In a sentence like this, Hebrew often uses the air where English might also say the air or just talk more generally about the weather.

בחוץ means outside or outdoors.

It is made from:

• ב־ = in / at
• חוץ = outside / the outside

So literally, בחוץ is something like outside or on the outside.

In this sentence, it works naturally as outside:

• האוויר בחוץ קר = The air outside is cold

Because in the present tense, Hebrew usually does not use a word for is / am / are.

So:

• האוויר קר literally looks like the air cold
• but it means the air is cold

This is completely normal Hebrew grammar.

Compare:

• המים קרים = The water is cold
• הילד עייף = The boy is tired
• אני מוכן = I am ready

In the past or future, Hebrew does use forms of to be, but in the present it usually leaves them out.

Because קר has to agree with האוויר, and אוויר is a masculine singular noun.

Hebrew adjectives agree with the noun in:

• gender
• number

So:

• masculine singular: קר
• feminine singular: קרה
• masculine plural: קרים
• feminine plural: קרות

Since אוויר is masculine singular, the correct form is קר.

Yes, אוויר is masculine.

In Hebrew, noun gender is not always predictable from meaning or spelling, so often you just have to learn it with the word.

That is why the adjective is:

• אוויר קר = cold air
• not אוויר קרה

A good habit is to learn new Hebrew nouns together with an adjective, so you remember their gender more easily.

Because Hebrew often puts the descriptive adjective or predicate adjective after the noun.

Here the structure is roughly:

• האוויר = the air
• בחוץ = outside
• קר = cold

So Hebrew is literally arranged like:

The air outside cold

This is normal for a sentence with a dropped present-tense is.

Also, Hebrew adjectives usually come after nouns:

• אוויר קר = cold air
• literally: air cold

So the word order here is very natural.

Yes. קר בחוץ is a very common sentence.

It means:

• It’s cold outside

The difference is mainly focus:

• קר בחוץ = a general statement about the conditions outside
• האוויר בחוץ קר = specifically the air outside is cold

So your sentence sounds a little more explicit and a little more focused on the air itself.

Its basic meaning is air.

In this sentence, though, English speakers may understand it almost like a comment about the weather, because saying the air outside is cold naturally describes the outdoor conditions.

Still, the word itself is air, not literally weather.

For weather, Hebrew uses מזג האוויר.

So:

• האוויר קר = The air is cold
• מזג האוויר קר is less natural, because cold usually describes the air or the day more directly than the weather itself

Yes, Hebrew allows some flexibility, but the meaning or emphasis can shift a little.

For example:

• האוויר בחוץ קר = The air outside is cold
• בחוץ האוויר קר = Outside, the air is cold
• האוויר קר בחוץ can also occur, but it may sound a bit less neutral depending on context

The version you have is a very natural, straightforward sentence.

They are related, but they are not the same kind of structure.

• אוויר קר = cold air
  This is a noun phrase, not a full sentence.
• האוויר בחוץ קר = The air outside is cold
  This is a full sentence.

So:

• אוויר קר נכנס לחדר = Cold air entered the room
• האוויר בחוץ קר = The air outside is cold

A useful way to think about it:

• אוויר קר describes a kind of air
• האוויר בחוץ קר makes a statement about the air outside

Because בחוץ is already a complete, standard Hebrew form meaning outside / outdoors.

It combines:

• ב־ = in / at
• חוץ = outside

Hebrew often builds everyday location words this way.

So you should learn בחוץ as a very common whole expression meaning:

• outside
• outdoors

You will hear it a lot in everyday speech.