Hot and humid in south, side close to Sicily (6)
I believe the answer is:
steamy
'hot and humid' is the definition.
(I've seen this before)
'south side close to sicily' is the wordplay.
'south' becomes 's' ('S' can be a synonym of 'south').
'side' becomes 'team' (I've seen this before**).
'close to' indicates one should take the final letters (the close/ending of).
The last letter of 'sicily' is 'y'.
's'+'team'+'y'='STEAMY'
'in' is the link.
(Other definitions for steamy that I've seen before include "Full of vapour; erotic (book)" , "Passionate" , "Erotic; like vapour" , "Salacious" , "My seat (anag.)" .)