Temperature is a physical quantity which can have various numeric values, which can be high or low. But I often read phrases like "cold temperature" and "hot temperature" on the Internet. A quantity can't be hot or cold, so these look odd to me, although I do understand what they mean. But English is not my native language, so my question is: are such phrases grammatically correct?
2 Answers
You are right. "Low temperature" is much better than "cold temperature".
"Cold temperature" is perfectly understandable, and you will hear people using it (so it isn't "wrong") but as you know the preferred form, you should use that.
Temperature can't be hot or cold -- such a construction is grammatically incorrect. As you correctly noted, temperature is measured numerically, so it can be high or low. Weather, on the other hand, can be modified with descriptive adjectives: I hate cold weather. I love hot-weather drinks.
Please keep in mind that the internet is a giant cesspool of unedited copy and grammatical errors. When in doubt, consult a usage book (I recommend Garner's Modern American Usage -- you can find a used copy online), or check to see whether The New Yorker (which has a great copy desk) has used a given phrase. This isn't foolproof -- most blogposts on its site aren't copy-edited, so TNY has published some errors -- but it's useful.
Use Google for such a search, because it shows you how many times the phrase appeared.
Ex.: site:newyorker.com "cold temperature"
PS: Your English is superb.