Start of showers and terrible April wind (6)
I believe the answer is:
spiral
'wind' is the definition.
(spiraling is a kind of winding)
'start of showers and terrible april' is the wordplay.
'start of' suggests taking the first letters.
'and' is a charade indicator (letters next to each other).
'terrible' indicates an anagram.
The first letter of 'showers' is 's'.
'april' with letters rearranged gives 'piral'.
's'+'piral'='SPIRAL'
(Other definitions for spiral that I've seen before include "Ever widening curve" , "Sir, pal inds in continuous loops" , "Like some staircases" , "Sir, pal winds in continuous loops" , "Whorl" .)