grammar/language nazi question: do we need the word "inclement"?
the word basically means bad weather. so, "inclement weather", the only use of the word "inclement" i've ever seen, means "bad weather weather". it's redundant. and also repetitive, too 
"inclemency" says it all. my commute today took longer than usual due to inclemency.
of course, as a practical matter, if i drop the word "inclemency" into casual conversation, people might not know what i mean; "inclement weather", especially in the context of however i'm using that phrase, usually makes what i'm intending to convey pretty clear.
"you're going on a trip? be sure to pack for inclemency"
"wtf you talking about, unblock?"
"i mean, be sure to pack for inclement weather"
"oh, got it, why didn't you say that in the first place?"
that said, strictly speaking, shouldn't we prefer the word "inclemency"?
= new reply since forum marked as read
It is in-KLEM-ent. It does not rhyme with "increment". 
Other than by meteorologists. Regular people don't say it. 
the word "gorgeous" always makes me think of ithaca, new york, because they "ithaca is gorgeous" because it has many gorges.
because an adjective (or adverb) describes only one particular noun does not make it a redundancy.
Normally, I'd agree with you re: "inclemency," except I can find only examples that also include "weather":
"Protection of interior of existing structures at all times from damage, dust and weather inclemency."
http://dictionary.reference.com/browse/inclemency
Moreover, trying to "educate" others on unusual or rare or even common-but-incorrect usages is a thankless task!
See: FORTE. 
1660s, from French inclément and directly from Latin inclementem (nominative inclemens) "harsh, unmerciful," from in- "not, opposite of, without" (see in- (1)) + clementem "mild, placid." "Limitation to weather is curious" {Weekley}.
inclemency (n.)
1550s, from Middle French inclémence and directly from Latin inclementia "rigor, harshness, roughness," from inclemens (see inclement).
Don't be so intemperate about a word
intemperate (adj.)
"characterized by excessive indulgence in a passion or appetite," late 14c., from Latin intemperatus "untempered, inclement, immoderate," from in- "not, opposite of" (see in- (1)) + temperantia (see temperance). Related: Intemperately.
