Nhiệt độ khá cao.

Vietnamese often does not use a verb equivalent to to be in simple descriptive sentences.

So:

• Nhiệt độ = temperature
• khá cao = quite high

Together, Nhiệt độ khá cao naturally means The temperature is quite high.

This is very common in Vietnamese:

• Trời đẹp = The weather is nice / It is nice out.
• Cô ấy cao = She is tall.

Khá is an adverb meaning something like quite, fairly, or rather.

In Nhiệt độ khá cao, it softens the statement a little compared with just saying Nhiệt độ cao.

Roughly:

• cao = high
• khá cao = quite/fairly high
• rất cao = very high

So khá suggests a noticeable degree, but usually less strong than rất.

In Vietnamese, degree words such as khá, rất, and hơi usually come before the adjective they modify.

So:

• cao = high
• khá cao = quite high
• rất cao = very high
• hơi cao = a little high

This is the normal Vietnamese word order: modifier + adjective

It is written as two separate syllables, nhiệt and độ, but together they form a single lexical item meaning temperature.

This is normal in Vietnamese. Many words are made of two syllables written with a space:

• học sinh = student
• xe đạp = bicycle
• nhiệt độ = temperature

So although it looks like two words to an English speaker, you should learn nhiệt độ as one unit of meaning.

A rough guide is:

• Nhiệt ≈ nyit with a clipped ending
• độ ≈ doh with a heavy falling-glottal tone
• khá ≈ kha with a rising tone
• cao ≈ cow (but smoother and without the English w feeling being too strong)

A few important pronunciation notes:

• nh sounds like the ny in canyon.
• đ is like a regular English d. It is different from plain d in Vietnamese.
• Tone marks matter a lot:
  • độ has the nặng tone
  • khá has the sắc tone
  • cao has no tone mark, so it has the level tone

If you want, I can also give a more detailed syllable-by-syllable pronunciation guide with tones.

Cao and nóng are different kinds of description.

• cao = high
• nóng = hot

For temperature, Vietnamese normally says the temperature is high/low:

• Nhiệt độ cao = The temperature is high
• Nhiệt độ thấp = The temperature is low

But for weather or physical sensation, Vietnamese often uses nóng:

• Trời nóng = It is hot
• Hôm nay nóng quá = It is very hot today

So Nhiệt độ khá cao sounds natural because it describes the level of the temperature, not the feeling of heat directly.

Yes, it can absolutely stand alone. Nhiệt độ is already the subject/topic of the sentence.

Vietnamese often allows short, complete statements like this:

• Giá cao. = The price is high.
• Phòng rộng. = The room is spacious.
• Nhiệt độ khá cao. = The temperature is quite high.

In context, Vietnamese can even omit the subject if it is obvious, but in this sentence the subject is already present.

It is neutral and natural. It works well in everyday speech, news, weather reports, and general writing.

It is a bit more neutral and factual than something like:

• Trời nóng quá. = It’s so hot.

So you might hear:

• in a weather report: Nhiệt độ hôm nay khá cao.
• in conversation: Hôm nay nhiệt độ khá cao.

No. That word order is not natural in standard Vietnamese.

The correct order is: adverb + adjective

• khá cao

So:

• Nhiệt độ khá cao = correct
• Nhiệt độ cao khá = incorrect

Vietnamese is fairly strict about this kind of modifier placement.

You can change the degree word before cao.

For example:

• Nhiệt độ hơi cao. = The temperature is a little high.
• Nhiệt độ khá cao. = The temperature is quite high.
• Nhiệt độ rất cao. = The temperature is very high.
• Nhiệt độ quá cao. = The temperature is too high.

So khá sits in the middle range: stronger than hơi, usually less strong than rất or quá.

Yes. Vietnamese commonly adds time or place expressions before or after the core sentence.

Examples:

• Hôm nay nhiệt độ khá cao. = Today the temperature is quite high.
• Nhiệt độ hôm nay khá cao. = The temperature today is quite high.
• Ở đây nhiệt độ khá cao. = The temperature here is quite high.
• Nhiệt độ ở Sài Gòn khá cao. = The temperature in Saigon is quite high.

Vietnamese is flexible with these added details, though some arrangements sound more natural depending on context.