From nation in South, rainy? Wrong! (6)
I believe the answer is:
syrian
'from nation' is the definition.
(from Syria)
'south rainy? wrong' is the wordplay.
'south' becomes 'S' (abbreviation).
'wrong' indicates anagramming the letters.
'rainy' anagrammed gives 'yrian'.
's'+'yrian'='SYRIAN'
'in' acts as a link.
(Other definitions for syrian that I've seen before include "Nationality of a citizen of Damascus" , "Damascus is this capital" , "ME national" , "One from Damascus, say" , "Eg, native to Damascus" .)