Intemperate, harsh (9)
I believe the answer is:
inclement
This clue is a double definition.
'intemperate' is the first definition.
(similar in meaning)
'harsh' is the second definition.
(both can describe bad weather)
(Other definitions for inclement that I've seen before include "bitter" , "(Of weather) cold or wet" , "(Of weather) bad" , "Weather so awful" , "severe" .)