bad weather vs inclementness

bad weather and inclementness both are nouns.

Word	Noun	Adjective	Verb	Adverb
bad weather	Yes	No	No	No
inclementness	Yes	No	No	No

As nouns, bad weather and inclementness are synonyms defined as:

bad weather and inclementness: weather unsuitable for outdoor activities

Other synonyms of bad weather include inclemency.

bad weather (noun)	inclementness (noun)
weather unsuitable for outdoor activities	weather unsuitable for outdoor activities