Wind, haze and rain at the beginning and end of April (7)
I believe the answer is:
mistral
'wind' is the definition.
(mistral is a kind of wind)
'haze and rain at the beginning and end of april' is the wordplay.
'haze' becomes 'mist' (I've seen this before).
'and' means one lot of letters go next to another.
'the beginning' indicates taking the first letters (I've seen 'the beginning of' mean this).
'and' is a charade indicator (letters next to each other).
'end of' says to take the final letters.
The initial letters of 'rain at' is 'ra'.
The last letter of 'april' is 'l'.
'mist'+'ra'+'l'='MISTRAL'
(Other definitions for mistral that I've seen before include "Cold dry wind in southern France" , "Famous wind in the Rhone Valley blowing towards the Med" , "Strong north wind of southern France" , "French wind" , "That's a blow" .)