Fog with beginnings of rain and light wind (7)
I believe the answer is:
mistral
'wind' is the definition.
(mistral is a kind of wind)
'fog with beginnings of rain and light' is the wordplay.
'fog' becomes 'mist' (mist is a kind of fog).
'with' is a charade indicator (letters next to each other).
'beginnings of' suggests taking the first letters (the beginning letters).
The first letters of 'rain and light' is 'ral'.
'mist'+'ral'='MISTRAL'
(Other definitions for mistral that I've seen before include "That's a blow" , "A harsh blow" , "Strong north wind of southern France" , "Nice chiller" , "Strong cold dry wind" .)