coolness vs low temperature

coolness and low temperature both are nouns.

Word	Noun	Adjective	Verb	Adverb
coolness	Yes	No	No	No
low temperature	Yes	No	No	No

As nouns, low temperature is a hypernym of coolness; that is, low temperature is a word with a broader meaning than coolness:

Other hypernyms of coolness include cold, coldness, frigidity, frigidness.

coolness (noun)	low temperature (noun)
the property of being moderately cold	the absence of heat
a lack of affection or enthusiasm
fearless self-possession in the face of danger
calm and unruffled self-assurance