sultriness vs weather condition

sultriness and weather condition both are nouns.

Word	Noun	Adjective	Verb	Adverb
sultriness	Yes	No	No	No
weather condition	Yes	No	No	No

As nouns, weather condition is a hypernym of sultriness; that is, weather condition is a word with a broader meaning than sultriness:

sultriness: oppressively hot and humid weather
weather condition: the atmospheric conditions that comprise the state of the atmosphere in terms of temperature and wind and clouds and precipitation

Other hypernyms of sultriness include atmospheric condition, conditions, weather.

sultriness (noun)	weather condition (noun)
the quality of expressing or arousing sexual desire	the atmospheric conditions that comprise the state of the atmosphere in terms of temperature and wind and clouds and precipitation
oppressively hot and humid weather