Antwerp is awfully wet and windy (9)
I believe the answer is:
rainswept
'wet and windy' is the definition.
(exposed to rain and wind)
'antwerp is awfully' is the wordplay.
'awfully' indicates anagramming the letters.
'antwerp'+'is'='antwerpis'
'antwerpis' is an anagram of 'RAINSWEPT'.
(Other definitions for rainswept that I've seen before include "Suffering cats and dogs" , "Thoroughly wet" , "exposed to regular lashing" , "Wet and stormy" .)