Grape is beset by wet weather (6)
I believe the answer is:
raisin
'grape' is the definition.
(a raisin is a dried grape)
'is beset by wet weather' is the wordplay.
'beset by' indicates putting letters inside ('beset' could historically mean 'cover').
'wet weather' becomes 'rain' (I've seen this before).
'is' put inside 'rain' is 'RAISIN'.
(Other definitions for raisin that I've seen before include "sultana, say" , "fruit product" , "A dried grape used in cake" , "Somewhat dry fruit" , "Cultivating" .)